haskell: Phase 17 — import declarations anywhere among top-level decls

hk-collect-module-body previously ran a fixed import-loop at the start and then a separate decl-loop; merged into a single hk-body-step dispatcher that routes `import` to the imports list and everything else to hk-parse-decl. Both call sites (initial step + post-semicolon loop) use the dispatcher. The eval side reads imports as a list (not by AST position) so mid-stream imports feed into hk-bind-decls! unchanged. tests/parse-extras.sx 12 → 17: very-top, mid-stream, post-main, two-imports-different-positions, unqualified-mid-file. Regression sweep clean: eval 66/0, exceptions 14/0, typecheck 15/0, records 14/0, ioref 13/0, map 26/0, set 17/0. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
haskell: Phase 17 — expression type annotations (x :: Int) (parse + desugar pass-through)
2026-05-10 19:11:36 +00:00 · 2026-05-08 23:12:35 +00:00 · 2026-05-08 22:41:22 +00:00 · 2026-05-08 07:06:28 +00:00 · 2026-05-08 00:17:46 +00:00 · 2026-05-07 20:35:28 +00:00
62 changed files with 6593 additions and 617 deletions
--- a/lib/apl/parser.sx
+++ b/lib/apl/parser.sx
@@ -25,8 +25,9 @@
 ; Glyph classification sets
 ; ============================================================

-(define apl-parse-op-glyphs
-  (list "/" "\\" "¨" "⍨" "∘" "." "⍣" "⍤" "⍥" "@"))
+(define
+  apl-parse-op-glyphs
+  (list "/" "⌿" "\\" "⍀" "¨" "⍨" "∘" "." "⍣" "⍤" "⍥" "@"))

 (define
  apl-parse-fn-glyphs
@@ -82,22 +83,48 @@
    "⍎"
    "⍕"))

-(define apl-quad-fn-names (list "⎕FMT"))
+(define apl-quad-fn-names (list "⎕FMT" "⎕←"))

-(define
-  apl-parse-op-glyph?
-  (fn (v) (some (fn (g) (= g v)) apl-parse-op-glyphs)))
+(define apl-known-fn-names (list))

 ; ============================================================
 ; Token accessors
 ; ============================================================

+(define
+  apl-collect-fn-bindings
+  (fn
+    (stmt-groups)
+    (set! apl-known-fn-names (list))
+    (for-each
+      (fn
+        (toks)
+        (when
+          (and
+            (>= (len toks) 3)
+            (= (tok-type (nth toks 0)) :name)
+            (= (tok-type (nth toks 1)) :assign)
+            (= (tok-type (nth toks 2)) :lbrace))
+          (set!
+            apl-known-fn-names
+            (cons (tok-val (nth toks 0)) apl-known-fn-names))))
+      stmt-groups)))
+
+(define
+  apl-parse-op-glyph?
+  (fn (v) (some (fn (g) (= g v)) apl-parse-op-glyphs)))
+
 (define
  apl-parse-fn-glyph?
  (fn (v) (some (fn (g) (= g v)) apl-parse-fn-glyphs)))

 (define tok-type (fn (tok) (get tok :type)))

+; ============================================================
+; Collect trailing operators starting at index i
+; Returns {:ops (op ...) :end new-i}
+; ============================================================
+
 (define tok-val (fn (tok) (get tok :value)))

 (define
@@ -107,8 +134,8 @@
    (and (= (tok-type tok) :glyph) (apl-parse-op-glyph? (tok-val tok)))))

 ; ============================================================
-; Collect trailing operators starting at index i
-; Returns {:ops (op ...) :end new-i}
+; Build a derived-fn node by chaining operators left-to-right
+; (+/¨  →  (:derived-fn "¨" (:derived-fn "/" (:fn-glyph "+"))))
 ; ============================================================

 (define
@@ -119,15 +146,17 @@
      (and (= (tok-type tok) :glyph) (apl-parse-fn-glyph? (tok-val tok)))
      (and
        (= (tok-type tok) :name)
-        (some (fn (q) (= q (tok-val tok))) apl-quad-fn-names)))))
+        (or
+          (some (fn (q) (= q (tok-val tok))) apl-quad-fn-names)
+          (some (fn (q) (= q (tok-val tok))) apl-known-fn-names))))))
+
+; ============================================================
+; Find matching close bracket/paren/brace
+; Returns the index of the matching close token
+; ============================================================

 (define collect-ops (fn (tokens i) (collect-ops-loop tokens i (list))))

-; ============================================================
-; Build a derived-fn node by chaining operators left-to-right
-; (+/¨  →  (:derived-fn "¨" (:derived-fn "/" (:fn-glyph "+"))))
-; ============================================================
-
 (define
  collect-ops-loop
  (fn
@@ -143,8 +172,10 @@
          {:end i :ops acc})))))

 ; ============================================================
-; Find matching close bracket/paren/brace
-; Returns the index of the matching close token
+; Segment collection: scan tokens left-to-right, building
+; a list of {:kind "val"/"fn" :node ast} segments.
+; Operators following function glyphs are merged into
+; derived-fn nodes during this pass.
 ; ============================================================

 (define
@@ -163,12 +194,20 @@
    (find-matching-close-loop tokens start open-type close-type 1)))

 ; ============================================================
-; Segment collection: scan tokens left-to-right, building
-; a list of {:kind "val"/"fn" :node ast} segments.
-; Operators following function glyphs are merged into
-; derived-fn nodes during this pass.
+; Build tree from segment list
+;
+; The segments are in left-to-right order.
+; APL evaluates right-to-left, so the LEFTMOST function is
+; the outermost (last-evaluated) node.
+;
+; Patterns:
+;   [val]              → val node
+;   [fn val ...]       → (:monad fn (build-tree rest))
+;   [val fn val ...]   → (:dyad fn val (build-tree rest))
+;   [val val ...]      → (:vec val1 val2 ...) — strand
 ; ============================================================

+; Find the index of the first function segment (returns -1 if none)
 (define
  find-matching-close-loop
  (fn
@@ -208,21 +247,9 @@
  collect-segments
  (fn (tokens) (collect-segments-loop tokens 0 (list))))

-; ============================================================
-; Build tree from segment list
-;
-; The segments are in left-to-right order.
-; APL evaluates right-to-left, so the LEFTMOST function is
-; the outermost (last-evaluated) node.
-;
-; Patterns:
-;   [val]              → val node
-;   [fn val ...]       → (:monad fn (build-tree rest))
-;   [val fn val ...]   → (:dyad fn val (build-tree rest))
-;   [val val ...]      → (:vec val1 val2 ...) — strand
-; ============================================================
-
-; Find the index of the first function segment (returns -1 if none)
+; Build an array node from 0..n value segments
+; If n=1 → return that segment's node
+; If n>1 → return (:vec node1 node2 ...)
 (define
  collect-segments-loop
  (fn
@@ -242,24 +269,38 @@
            ((= tt :str)
              (collect-segments-loop tokens (+ i 1) (append acc {:kind "val" :node (list :str tv)})))
            ((= tt :name)
-              (if
-                (some (fn (q) (= q tv)) apl-quad-fn-names)
-                (let
-                  ((op-result (collect-ops tokens (+ i 1))))
+              (cond
+                ((some (fn (q) (= q tv)) apl-quad-fn-names)
                  (let
-                    ((ops (get op-result :ops)) (ni (get op-result :end)))
+                    ((op-result (collect-ops tokens (+ i 1))))
                    (let
-                      ((fn-node (build-derived-fn (list :fn-glyph tv) ops)))
-                      (collect-segments-loop
-                        tokens
-                        ni
-                        (append acc {:kind "fn" :node fn-node})))))
-                (let
-                  ((br (maybe-bracket (list :name tv) tokens (+ i 1))))
-                  (collect-segments-loop
-                    tokens
-                    (nth br 1)
-                    (append acc {:kind "val" :node (nth br 0)})))))
+                      ((ops (get op-result :ops))
+                        (ni (get op-result :end)))
+                      (let
+                        ((fn-node (build-derived-fn (list :fn-glyph tv) ops)))
+                        (collect-segments-loop
+                          tokens
+                          ni
+                          (append acc {:kind "fn" :node fn-node}))))))
+                ((some (fn (q) (= q tv)) apl-known-fn-names)
+                  (let
+                    ((op-result (collect-ops tokens (+ i 1))))
+                    (let
+                      ((ops (get op-result :ops))
+                        (ni (get op-result :end)))
+                      (let
+                        ((fn-node (build-derived-fn (list :fn-name tv) ops)))
+                        (collect-segments-loop
+                          tokens
+                          ni
+                          (append acc {:kind "fn" :node fn-node}))))))
+                (else
+                  (let
+                    ((br (maybe-bracket (list :name tv) tokens (+ i 1))))
+                    (collect-segments-loop
+                      tokens
+                      (nth br 1)
+                      (append acc {:kind "val" :node (nth br 0)}))))))
            ((= tt :lparen)
              (let
                ((end (find-matching-close tokens (+ i 1) :lparen :rparen)))
@@ -267,11 +308,23 @@
                  ((inner-tokens (slice tokens (+ i 1) end))
                    (after (+ end 1)))
                  (let
-                    ((br (maybe-bracket (parse-apl-expr inner-tokens) tokens after)))
-                    (collect-segments-loop
-                      tokens
-                      (nth br 1)
-                      (append acc {:kind "val" :node (nth br 0)}))))))
+                    ((inner-segs (collect-segments inner-tokens)))
+                    (if
+                      (and
+                        (>= (len inner-segs) 2)
+                        (every? (fn (s) (= (get s :kind) "fn")) inner-segs))
+                      (let
+                        ((train-node (cons :train (map (fn (s) (get s :node)) inner-segs))))
+                        (collect-segments-loop
+                          tokens
+                          after
+                          (append acc {:kind "fn" :node train-node})))
+                      (let
+                        ((br (maybe-bracket (parse-apl-expr inner-tokens) tokens after)))
+                        (collect-segments-loop
+                          tokens
+                          (nth br 1)
+                          (append acc {:kind "val" :node (nth br 0)}))))))))
            ((= tt :lbrace)
              (let
                ((end (find-matching-close tokens (+ i 1) :lbrace :rbrace)))
@@ -346,9 +399,12 @@

 (define find-first-fn (fn (segs) (find-first-fn-loop segs 0)))

-; Build an array node from 0..n value segments
-; If n=1 → return that segment's node
-; If n>1 → return (:vec node1 node2 ...)
+
+; ============================================================
+; Split token list on statement separators (diamond / newline)
+; Only splits at depth 0 (ignores separators inside { } or ( ) )
+; ============================================================
+
 (define
  find-first-fn-loop
  (fn
@@ -370,10 +426,9 @@
      (get (first segs) :node)
      (cons :vec (map (fn (s) (get s :node)) segs)))))

-
 ; ============================================================
-; Split token list on statement separators (diamond / newline)
-; Only splits at depth 0 (ignores separators inside { } or ( ) )
+; Parse a dfn body (tokens between { and })
+; Handles guard expressions: cond : expr
 ; ============================================================

 (define
@@ -408,11 +463,6 @@
  split-statements
  (fn (tokens) (split-statements-loop tokens (list) (list) 0)))

-; ============================================================
-; Parse a dfn body (tokens between { and })
-; Handles guard expressions: cond : expr
-; ============================================================
-
 (define
  split-statements-loop
  (fn
@@ -467,6 +517,10 @@
      ((stmt-groups (split-statements tokens)))
      (let ((stmts (map parse-dfn-stmt stmt-groups))) (cons :dfn stmts)))))

+; ============================================================
+; Parse a single statement (assignment or expression)
+; ============================================================
+
 (define
  parse-dfn-stmt
  (fn
@@ -483,12 +537,17 @@
            (parse-apl-expr body-tokens)))
        (parse-stmt tokens)))))

+; ============================================================
+; Parse an expression from a flat token list
+; ============================================================
+
 (define
  find-top-level-colon
  (fn (tokens i) (find-top-level-colon-loop tokens i 0)))

 ; ============================================================
-; Parse a single statement (assignment or expression)
+; Main entry point
+; parse-apl: string → AST
 ; ============================================================

 (define
@@ -508,10 +567,6 @@
          ((and (= tt :colon) (= depth 0)) i)
          (true (find-top-level-colon-loop tokens (+ i 1) depth)))))))

-; ============================================================
-; Parse an expression from a flat token list
-; ============================================================
-
 (define
  parse-stmt
  (fn
@@ -526,11 +581,6 @@
        (parse-apl-expr (slice tokens 2)))
      (parse-apl-expr tokens))))

-; ============================================================
-; Main entry point
-; parse-apl: string → AST
-; ============================================================
-
 (define
  parse-apl-expr
  (fn
@@ -547,13 +597,52 @@
      ((tokens (apl-tokenize src)))
      (let
        ((stmt-groups (split-statements tokens)))
-        (if
-          (= (len stmt-groups) 0)
-          nil
+        (begin
+          (apl-collect-fn-bindings stmt-groups)
          (if
-            (= (len stmt-groups) 1)
-            (parse-stmt (first stmt-groups))
-            (cons :program (map parse-stmt stmt-groups))))))))
+            (= (len stmt-groups) 0)
+            nil
+            (if
+              (= (len stmt-groups) 1)
+              (parse-stmt (first stmt-groups))
+              (cons :program (map parse-stmt stmt-groups)))))))))
+
+(define
+  split-bracket-loop
+  (fn
+    (tokens current acc depth)
+    (if
+      (= (len tokens) 0)
+      (append acc (list current))
+      (let
+        ((tok (first tokens)) (more (rest tokens)))
+        (let
+          ((tt (tok-type tok)))
+          (cond
+            ((or (= tt :lparen) (= tt :lbrace) (= tt :lbracket))
+              (split-bracket-loop
+                more
+                (append current (list tok))
+                acc
+                (+ depth 1)))
+            ((or (= tt :rparen) (= tt :rbrace) (= tt :rbracket))
+              (split-bracket-loop
+                more
+                (append current (list tok))
+                acc
+                (- depth 1)))
+            ((and (= tt :semi) (= depth 0))
+              (split-bracket-loop
+                more
+                (list)
+                (append acc (list current))
+                depth))
+            (else
+              (split-bracket-loop more (append current (list tok)) acc depth))))))))
+
+(define
+  split-bracket-content
+  (fn (tokens) (split-bracket-loop tokens (list) (list) 0)))

 (define
  maybe-bracket
@@ -569,8 +658,17 @@
          ((inner-tokens (slice tokens (+ after 1) end))
            (next-after (+ end 1)))
          (let
-            ((idx-expr (parse-apl-expr inner-tokens)))
-            (let
-              ((indexed (list :dyad (list :fn-glyph "⌷") idx-expr val-node)))
-              (maybe-bracket indexed tokens next-after)))))
+            ((sections (split-bracket-content inner-tokens)))
+            (if
+              (= (len sections) 1)
+              (let
+                ((idx-expr (parse-apl-expr inner-tokens)))
+                (let
+                  ((indexed (list :dyad (list :fn-glyph "⌷") idx-expr val-node)))
+                  (maybe-bracket indexed tokens next-after)))
+              (let
+                ((axis-exprs (map (fn (toks) (if (= (len toks) 0) :all (parse-apl-expr toks))) sections)))
+                (let
+                  ((indexed (cons :bracket (cons val-node axis-exprs))))
+                  (maybe-bracket indexed tokens next-after)))))))
      (list val-node after))))
--- a/lib/apl/runtime.sx
+++ b/lib/apl/runtime.sx
@@ -883,7 +883,7 @@
      (let
        ((sub (apl-permutations (- n 1))))
        (reduce
-          (fn (acc p) (append acc (apl-insert-everywhere n p)))
+          (fn (acc p) (append (apl-insert-everywhere n p) acc))
          (list)
          sub)))))

@@ -985,6 +985,38 @@
        (some (fn (c) (= c 0)) codes)
        (some (fn (c) (= c (nth e 1))) codes)))))

+(define
+  apl-cartesian
+  (fn
+    (lists)
+    (if
+      (= (len lists) 0)
+      (list (list))
+      (let
+        ((rest-prods (apl-cartesian (rest lists))))
+        (reduce
+          (fn (acc x) (append acc (map (fn (p) (cons x p)) rest-prods)))
+          (list)
+          (first lists))))))
+
+(define
+  apl-bracket-multi
+  (fn
+    (axes arr)
+    (let
+      ((shape (get arr :shape)) (ravel (get arr :ravel)))
+      (let
+        ((rank (len shape)) (strides (apl-strides shape)))
+        (let
+          ((axis-info (map (fn (i) (let ((a (nth axes i))) (cond ((= a nil) {:idxs (range 0 (nth shape i)) :scalar? false}) ((= (len (get a :shape)) 0) {:idxs (list (- (first (get a :ravel)) apl-io)) :scalar? true}) (else {:idxs (map (fn (x) (- x apl-io)) (get a :ravel)) :scalar? false})))) (range 0 rank))))
+          (let
+            ((cells (apl-cartesian (map (fn (a) (get a :idxs)) axis-info))))
+            (let
+              ((result-ravel (map (fn (cell) (let ((flat (reduce + 0 (map (fn (i) (* (nth cell i) (nth strides i))) (range 0 rank))))) (nth ravel flat))) cells)))
+              (let
+                ((result-shape (filter (fn (x) (>= x 0)) (map (fn (i) (let ((a (nth axis-info i))) (if (get a :scalar?) -1 (len (get a :idxs))))) (range 0 rank)))))
+                (make-array result-shape result-ravel)))))))))
+
 (define
  apl-reduce
  (fn
--- a/lib/apl/test.sh
+++ b/lib/apl/test.sh
@@ -39,6 +39,7 @@ cat > "$TMPFILE" << 'EPOCHS'
 (load "lib/apl/tests/idioms.sx")
 (load "lib/apl/tests/eval-ops.sx")
 (load "lib/apl/tests/pipeline.sx")
+(load "lib/apl/tests/programs-e2e.sx")
 (epoch 4)
 (eval "(list apl-test-pass apl-test-fail)")
 EPOCHS
--- a/lib/apl/tests/pipeline.sx
+++ b/lib/apl/tests/pipeline.sx
@@ -178,3 +178,137 @@
  "apl-run \"(⍳5)[3] × 7\" → 21"
  (mkrv (apl-run "(⍳5)[3] × 7"))
  (list 21))
+
+(apl-test "decimal: 3.7 → 3.7" (mkrv (apl-run "3.7")) (list 3.7))
+
+(apl-test "decimal: ¯2.5 → -2.5" (mkrv (apl-run "¯2.5")) (list -2.5))
+
+(apl-test "decimal: 1.5 + 2.5 → 4" (mkrv (apl-run "1.5 + 2.5")) (list 4))
+
+(apl-test "decimal: ⌊3.7 → 3" (mkrv (apl-run "⌊ 3.7")) (list 3))
+
+(apl-test "decimal: ⌈3.7 → 4" (mkrv (apl-run "⌈ 3.7")) (list 4))
+
+(apl-test
+  "⎕← scalar passthrough"
+  (mkrv (apl-run "⎕← 42"))
+  (list 42))
+
+(apl-test
+  "⎕← vector passthrough"
+  (mkrv (apl-run "⎕← 1 2 3"))
+  (list 1 2 3))
+
+(apl-test
+  "string: 'abc' → 3-char vector"
+  (mkrv (apl-run "'abc'"))
+  (list "a" "b" "c"))
+
+(apl-test "string: 'a' is rank-0 scalar" (mksh (apl-run "'a'")) (list))
+
+(apl-test "string: 'hello' shape (5)" (mksh (apl-run "'hello'")) (list 5))
+
+(apl-test
+  "named-fn: f ← {⍺+⍵} ⋄ 3 f 4 → 7"
+  (mkrv (apl-run "f ← {⍺+⍵} ⋄ 3 f 4"))
+  (list 7))
+
+(apl-test
+  "named-fn monadic: sq ← {⍵×⍵} ⋄ sq 7 → 49"
+  (mkrv (apl-run "sq ← {⍵×⍵} ⋄ sq 7"))
+  (list 49))
+
+(apl-test
+  "named-fn dyadic: hyp ← {((⍺×⍺)+⍵×⍵)} ⋄ 3 hyp 4 → 25"
+  (mkrv (apl-run "hyp ← {((⍺×⍺)+⍵×⍵)} ⋄ 3 hyp 4"))
+  (list 25))
+
+(apl-test
+  "named-fn: dbl ← {⍵+⍵} ⋄ dbl ⍳5"
+  (mkrv (apl-run "dbl ← {⍵+⍵} ⋄ dbl ⍳5"))
+  (list 2 4 6 8 10))
+
+(apl-test
+  "named-fn factorial via ∇ recursion"
+  (mkrv (apl-run "fact ← {0=⍵:1 ⋄ ⍵×∇⍵-1} ⋄ fact 5"))
+  (list 120))
+
+(apl-test
+  "named-fn used twice in expr: dbl ← {⍵+⍵} ⋄ (dbl 3) + dbl 4"
+  (mkrv (apl-run "dbl ← {⍵+⍵} ⋄ (dbl 3) + dbl 4"))
+  (list 14))
+
+(apl-test
+  "named-fn with vector arg: neg ← {-⍵} ⋄ neg 1 2 3"
+  (mkrv (apl-run "neg ← {-⍵} ⋄ neg 1 2 3"))
+  (list -1 -2 -3))
+
+(apl-test
+  "multi-axis: M[2;2] → center"
+  (mkrv (apl-run "M ← (3 3) ⍴ ⍳9 ⋄ M[2;2]"))
+  (list 5))
+
+(apl-test
+  "multi-axis: M[1;] → first row"
+  (mkrv (apl-run "M ← (3 3) ⍴ ⍳9 ⋄ M[1;]"))
+  (list 1 2 3))
+
+(apl-test
+  "multi-axis: M[;2] → second column"
+  (mkrv (apl-run "M ← (3 3) ⍴ ⍳9 ⋄ M[;2]"))
+  (list 2 5 8))
+
+(apl-test
+  "multi-axis: M[1 2;1 2] → 2x2 block"
+  (mkrv (apl-run "M ← (2 3) ⍴ ⍳6 ⋄ M[1 2;1 2]"))
+  (list 1 2 4 5))
+
+(apl-test
+  "multi-axis: M[1 2;1 2] shape (2 2)"
+  (mksh (apl-run "M ← (2 3) ⍴ ⍳6 ⋄ M[1 2;1 2]"))
+  (list 2 2))
+
+(apl-test
+  "multi-axis: M[;] full matrix"
+  (mkrv (apl-run "M ← (2 2) ⍴ 10 20 30 40 ⋄ M[;]"))
+  (list 10 20 30 40))
+
+(apl-test
+  "multi-axis: M[1;] shape collapsed"
+  (mksh (apl-run "M ← (3 3) ⍴ ⍳9 ⋄ M[1;]"))
+  (list 3))
+
+(apl-test
+  "multi-axis: select all rows of column 3"
+  (mkrv (apl-run "M ← (4 3) ⍴ 1 2 3 4 5 6 7 8 9 10 11 12 ⋄ M[;3]"))
+  (list 3 6 9 12))
+
+(apl-test
+  "train: mean = (+/÷≢) on 1..5"
+  (mkrv (apl-run "(+/÷≢) 1 2 3 4 5"))
+  (list 3))
+
+(apl-test
+  "train: mean of 2 4 6 8 10"
+  (mkrv (apl-run "(+/÷≢) 2 4 6 8 10"))
+  (list 6))
+
+(apl-test
+  "train 2-atop: (- ⌊) 5 → -5"
+  (mkrv (apl-run "(- ⌊) 5"))
+  (list -5))
+
+(apl-test
+  "train 3-fork dyadic: 2(+×-)5 → -21"
+  (mkrv (apl-run "2 (+ × -) 5"))
+  (list -21))
+
+(apl-test
+  "train: range = (⌈/-⌊/) on vector"
+  (mkrv (apl-run "(⌈/-⌊/) 3 1 4 1 5 9 2 6"))
+  (list 8))
+
+(apl-test
+  "train: mean of ⍳10 has shape ()"
+  (mksh (apl-run "(+/÷≢) ⍳10"))
+  (list))
--- a/lib/apl/tests/programs-e2e.sx
+++ b/lib/apl/tests/programs-e2e.sx
@@ -0,0 +1,96 @@
+; End-to-end tests of the classic-program archetypes — running APL
+; source through the full pipeline (tokenize → parse → eval-ast → runtime).
+;
+; These mirror the algorithms documented in lib/apl/tests/programs/*.apl
+; but use forms our pipeline supports today (named functions instead of
+; the inline ⍵← rebinding idiom; multi-stmt over single one-liners).
+
+(define mkrv (fn (arr) (get arr :ravel)))
+(define mksh (fn (arr) (get arr :shape)))
+
+; ---------- factorial via ∇ recursion (cf. n-queens style) ----------
+
+(apl-test
+  "e2e: factorial 5! = 120"
+  (mkrv (apl-run "fact ← {0=⍵:1 ⋄ ⍵×∇⍵-1} ⋄ fact 5"))
+  (list 120))
+
+(apl-test
+  "e2e: factorial 7! = 5040"
+  (mkrv (apl-run "fact ← {0=⍵:1 ⋄ ⍵×∇⍵-1} ⋄ fact 7"))
+  (list 5040))
+
+(apl-test
+  "e2e: factorial via ×/⍳N (no recursion)"
+  (mkrv (apl-run "fact ← {×/⍳⍵} ⋄ fact 6"))
+  (list 720))
+
+; ---------- sum / triangular numbers (sum-1..N) ----------
+
+(apl-test
+  "e2e: triangular(10) = 55"
+  (mkrv (apl-run "tri ← {+/⍳⍵} ⋄ tri 10"))
+  (list 55))
+
+(apl-test
+  "e2e: triangular(100) = 5050"
+  (mkrv (apl-run "tri ← {+/⍳⍵} ⋄ tri 100"))
+  (list 5050))
+
+; ---------- sum of squares ----------
+
+(apl-test
+  "e2e: sum-of-squares 1..5 = 55"
+  (mkrv (apl-run "ss ← {+/⍵×⍵} ⋄ ss ⍳5"))
+  (list 55))
+
+(apl-test
+  "e2e: sum-of-squares 1..10 = 385"
+  (mkrv (apl-run "ss ← {+/⍵×⍵} ⋄ ss ⍳10"))
+  (list 385))
+
+; ---------- divisor-counting (prime-sieve building blocks) ----------
+
+(apl-test
+  "e2e: divisor counts 1..5 via outer mod"
+  (mkrv (apl-run "P ← ⍳ 5 ⋄ +⌿ 0 = P ∘.| P"))
+  (list 1 2 2 3 2))
+
+(apl-test
+  "e2e: divisor counts 1..10"
+  (mkrv (apl-run "P ← ⍳ 10 ⋄ +⌿ 0 = P ∘.| P"))
+  (list 1 2 2 3 2 4 2 4 3 4))
+
+(apl-test
+  "e2e: prime-mask 1..10 (count==2)"
+  (mkrv (apl-run "P ← ⍳ 10 ⋄ 2 = +⌿ 0 = P ∘.| P"))
+  (list 0 1 1 0 1 0 1 0 0 0))
+
+; ---------- monadic primitives chained ----------
+
+(apl-test
+  "e2e: sum of |abs| = 15"
+  (mkrv (apl-run "+/|¯1 ¯2 ¯3 ¯4 ¯5"))
+  (list 15))
+
+(apl-test
+  "e2e: max of squares 1..6"
+  (mkrv (apl-run "⌈/(⍳6)×⍳6"))
+  (list 36))
+
+; ---------- nested named functions ----------
+
+(apl-test
+  "e2e: compose dbl and sq via two named fns"
+  (mkrv (apl-run "dbl ← {⍵+⍵} ⋄ sq ← {⍵×⍵} ⋄ sq dbl 3"))
+  (list 36))
+
+(apl-test
+  "e2e: max-of-two as named dyadic fn"
+  (mkrv (apl-run "mx ← {⍺⌈⍵} ⋄ 5 mx 3"))
+  (list 5))
+
+(apl-test
+  "e2e: sqrt-via-newton 1 step from 1 → 2.5"
+  (mkrv (apl-run "step ← {(⍵+⍺÷⍵)÷2} ⋄ 4 step 1"))
+  (list 2.5))
--- a/lib/apl/tests/programs.sx
+++ b/lib/apl/tests/programs.sx
@@ -252,6 +252,8 @@

 (apl-test "queens 7 → 40 solutions" (mkrv (apl-queens 7)) (list 40))

+(apl-test "queens 8 → 92 solutions" (mkrv (apl-queens 8)) (list 92))
+
 (apl-test "permutations of 3 has 6" (len (apl-permutations 3)) 6)

 (apl-test "permutations of 4 has 24" (len (apl-permutations 4)) 24)
--- a/lib/apl/tokenizer.sx
+++ b/lib/apl/tokenizer.sx
@@ -2,7 +2,7 @@
  (list "+" "-" "×" "÷" "*" "⍟" "⌈" "⌊" "|" "!" "?" "○" "~" "<" "≤" "=" "≥" ">" "≠"
        "≢" "≡" "∊" "∧" "∨" "⍱" "⍲" "," "⍪" "⍴" "⌽" "⊖" "⍉" "↑" "↓" "⊂" "⊃" "⊆"
        "∪" "∩" "⍳" "⍸" "⌷" "⍋" "⍒" "⊥" "⊤" "⊣" "⊢" "⍎" "⍕"
-        "⍺" "⍵" "∇" "/" "\\" "¨" "⍨" "∘" "." "⍣" "⍤" "⍥" "@" "¯"))
+        "⍺" "⍵" "∇" "/" "⌿" "\\" "⍀" "¨" "⍨" "∘" "." "⍣" "⍤" "⍥" "@" "¯"))

 (define apl-glyph?
  (fn (ch)
@@ -138,12 +138,22 @@
                 (begin
                   (consume! "¯")
                   (let ((digits (read-digits! "")))
-                     (tok-push! :num (- 0 (parse-int digits 0))))
+                     (if (and (< pos src-len) (= (cur-byte) ".")
+                              (< (+ pos 1) src-len) (apl-digit? (nth source (+ pos 1))))
+                       (begin (advance!)
+                              (let ((frac (read-digits! "")))
+                                (tok-push! :num (- 0 (string->number (str digits "." frac))))))
+                       (tok-push! :num (- 0 (parse-int digits 0)))))
                   (scan!)))
                ((apl-digit? ch)
                 (begin
                   (let ((digits (read-digits! "")))
-                     (tok-push! :num (parse-int digits 0)))
+                     (if (and (< pos src-len) (= (cur-byte) ".")
+                              (< (+ pos 1) src-len) (apl-digit? (nth source (+ pos 1))))
+                       (begin (advance!)
+                              (let ((frac (read-digits! "")))
+                                (tok-push! :num (string->number (str digits "." frac)))))
+                       (tok-push! :num (parse-int digits 0))))
                   (scan!)))
                ((= ch "'")
                 (begin
@@ -155,7 +165,9 @@
                 (let ((start pos))
                   (begin
                     (if (cur-sw? "⎕") (consume! "⎕") (advance!))
-                     (read-ident-cont!)
+                     (if (and (< pos src-len) (cur-sw? "←"))
+                       (consume! "←")
+                       (read-ident-cont!))
                     (tok-push! :name (slice source start pos))
                     (scan!))))
                (true
--- a/lib/apl/transpile.sx
+++ b/lib/apl/transpile.sx
@@ -40,6 +40,7 @@
      ((= g "⍋") apl-grade-up)
      ((= g "⍒") apl-grade-down)
      ((= g "⎕FMT") apl-quad-fmt)
+      ((= g "⎕←") apl-quad-print)
      (else (error "no monadic fn for glyph")))))

 (define
@@ -97,6 +98,15 @@
      ((tag (first node)))
      (cond
        ((= tag :num) (apl-scalar (nth node 1)))
+        ((= tag :str)
+          (let
+            ((s (nth node 1)))
+            (if
+              (= (len s) 1)
+              (apl-scalar s)
+              (make-array
+                (list (len s))
+                (map (fn (i) (slice s i (+ i 1))) (range 0 (len s)))))))
        ((= tag :vec)
          (let
            ((items (rest node)))
@@ -139,6 +149,16 @@
                (apl-eval-ast rhs env)))))
        ((= tag :program) (apl-eval-stmts (rest node) env))
        ((= tag :dfn) node)
+        ((= tag :bracket)
+          (let
+            ((arr-expr (nth node 1)) (axis-exprs (rest (rest node))))
+            (let
+              ((arr (apl-eval-ast arr-expr env))
+                (axes
+                  (map
+                    (fn (a) (if (= a :all) nil (apl-eval-ast a env)))
+                    axis-exprs)))
+              (apl-bracket-multi axes arr))))
        (else (error (list "apl-eval-ast: unknown node tag" tag node)))))))

 (define
@@ -419,6 +439,36 @@
                  ((f (apl-resolve-dyadic inner env)))
                  (fn (arr) (apl-commute f arr))))
              (else (error "apl-resolve-monadic: unsupported op")))))
+        ((= tag :fn-name)
+          (let
+            ((nm (nth fn-node 1)))
+            (let
+              ((bound (get env nm)))
+              (if
+                (and
+                  (list? bound)
+                  (> (len bound) 0)
+                  (= (first bound) :dfn))
+                (fn (arg) (apl-call-dfn-m bound arg))
+                (error "apl-resolve-monadic: name not bound to dfn")))))
+        ((= tag :train)
+          (let
+            ((fns (rest fn-node)))
+            (let
+              ((n (len fns)))
+              (cond
+                ((= n 2)
+                  (let
+                    ((g (apl-resolve-monadic (nth fns 0) env))
+                      (h (apl-resolve-monadic (nth fns 1) env)))
+                    (fn (arg) (g (h arg)))))
+                ((= n 3)
+                  (let
+                    ((f (apl-resolve-monadic (nth fns 0) env))
+                      (g (apl-resolve-dyadic (nth fns 1) env))
+                      (h (apl-resolve-monadic (nth fns 2) env)))
+                    (fn (arg) (g (f arg) (h arg)))))
+                (else (error "monadic train arity not 2 or 3"))))))
        (else (error "apl-resolve-monadic: unknown fn-node tag"))))))

 (define
@@ -442,6 +492,18 @@
                  ((f (apl-resolve-dyadic inner env)))
                  (fn (a b) (apl-commute-dyadic f a b))))
              (else (error "apl-resolve-dyadic: unsupported op")))))
+        ((= tag :fn-name)
+          (let
+            ((nm (nth fn-node 1)))
+            (let
+              ((bound (get env nm)))
+              (if
+                (and
+                  (list? bound)
+                  (> (len bound) 0)
+                  (= (first bound) :dfn))
+                (fn (a b) (apl-call-dfn bound a b))
+                (error "apl-resolve-dyadic: name not bound to dfn")))))
        ((= tag :outer)
          (let
            ((inner (nth fn-node 2)))
@@ -455,6 +517,24 @@
              ((f (apl-resolve-dyadic f-node env))
                (g (apl-resolve-dyadic g-node env)))
              (fn (a b) (apl-inner f g a b)))))
+        ((= tag :train)
+          (let
+            ((fns (rest fn-node)))
+            (let
+              ((n (len fns)))
+              (cond
+                ((= n 2)
+                  (let
+                    ((g (apl-resolve-monadic (nth fns 0) env))
+                      (h (apl-resolve-dyadic (nth fns 1) env)))
+                    (fn (a b) (g (h a b)))))
+                ((= n 3)
+                  (let
+                    ((f (apl-resolve-dyadic (nth fns 0) env))
+                      (g (apl-resolve-dyadic (nth fns 1) env))
+                      (h (apl-resolve-dyadic (nth fns 2) env)))
+                    (fn (a b) (g (f a b) (h a b)))))
+                (else (error "dyadic train arity not 2 or 3"))))))
        (else (error "apl-resolve-dyadic: unknown fn-node tag"))))))

 (define apl-run (fn (src) (apl-eval-ast (parse-apl src) {})))
--- a/lib/guest/hm.sx
+++ b/lib/guest/hm.sx
@@ -0,0 +1,180 @@
+;; lib/guest/hm.sx — Hindley-Milner type-inference foundations.
+;;
+;; Builds on lib/guest/match.sx (terms + unify) and ast.sx (canonical
+;; AST shapes). This file ships the ALGEBRA — types, schemes, free
+;; type-vars, generalize / instantiate, substitution composition — so a
+;; full Algorithm W (or J) can be assembled on top either inside this
+;; file or in a host-specific consumer (haskell/infer.sx,
+;; lib/ocaml/types.sx, …).
+;;
+;; Per the brief the second consumer for this step is OCaml-on-SX
+;; Phase 5 (paired sequencing). Until that lands, the algebra is the
+;; deliverable; the host-flavoured assembly (lambda / app / let
+;; inference rules with substitution threading) lives in the host.
+;;
+;; Types
+;; -----
+;; A type is a canonical match.sx term — type variables use mk-var,
+;; type constructors use mk-ctor:
+;;   (hm-tv NAME)              type variable
+;;   (hm-arrow A B)             A -> B
+;;   (hm-con NAME ARGS)         named n-ary constructor
+;;   (hm-int) / (hm-bool) / (hm-string)   primitive constructors
+;;
+;; Schemes
+;; -------
+;;   (hm-scheme VARS TYPE)        ∀ VARS . TYPE
+;;   (hm-monotype TYPE)           empty quantifier
+;;   (hm-scheme? S) (hm-scheme-vars S) (hm-scheme-type S)
+;;
+;; Free type variables
+;; -------------------
+;;   (hm-ftv TYPE)                names occurring in TYPE
+;;   (hm-ftv-scheme S)            free names (minus quantifiers)
+;;   (hm-ftv-env ENV)             free across an env (name -> scheme)
+;;
+;; Substitution
+;; ------------
+;;   (hm-apply SUBST TYPE)        substitute through a type
+;;   (hm-apply-scheme SUBST S)    leaves bound vars alone
+;;   (hm-apply-env SUBST ENV)
+;;   (hm-compose S2 S1)           apply S1 then S2
+;;
+;; Generalize / Instantiate
+;; ------------------------
+;;   (hm-generalize TYPE ENV)      → scheme over ftv(t) - ftv(env)
+;;   (hm-instantiate SCHEME COUNTER) → fresh-var instance
+;;   (hm-fresh-tv COUNTER)         → (:var "tN"), bumps COUNTER
+;;
+;; Inference (literal only — the rest of Algorithm W lives in the host)
+;; --------------------------------------------------------------------
+;;   (hm-infer-literal EXPR)       → {:subst {} :type T}
+;;
+;; A complete Algorithm W consumes this kit by assembling lambda / app
+;; / let rules in the host language file.
+
+(define hm-tv     (fn (name) (list :var name)))
+(define hm-con    (fn (name args) (list :ctor name args)))
+(define hm-arrow  (fn (a b) (hm-con "->" (list a b))))
+(define hm-int    (fn () (hm-con "Int" (list))))
+(define hm-bool   (fn () (hm-con "Bool" (list))))
+(define hm-string (fn () (hm-con "String" (list))))
+
+(define hm-scheme        (fn (vars t) (list :scheme vars t)))
+(define hm-monotype      (fn (t) (hm-scheme (list) t)))
+(define hm-scheme?       (fn (s) (and (list? s) (not (empty? s)) (= (first s) :scheme))))
+(define hm-scheme-vars   (fn (s) (nth s 1)))
+(define hm-scheme-type   (fn (s) (nth s 2)))
+
+(define
+  hm-fresh-tv
+  (fn (counter)
+    (let ((n (first counter)))
+      (begin
+        (set-nth! counter 0 (+ n 1))
+        (hm-tv (str "t" (+ n 1)))))))
+
+(define
+  hm-ftv-acc
+  (fn (t acc)
+    (cond
+      ((is-var? t)
+        (if (some (fn (n) (= n (var-name t))) acc) acc (cons (var-name t) acc)))
+      ((is-ctor? t)
+        (let ((a acc))
+          (begin
+            (for-each (fn (x) (set! a (hm-ftv-acc x a))) (ctor-args t))
+            a)))
+      (:else acc))))
+
+(define hm-ftv (fn (t) (hm-ftv-acc t (list))))
+
+(define
+  hm-ftv-scheme
+  (fn (s)
+    (let ((qs (hm-scheme-vars s))
+          (all (hm-ftv (hm-scheme-type s))))
+      (filter (fn (n) (not (some (fn (q) (= q n)) qs))) all))))
+
+(define
+  hm-ftv-env
+  (fn (env)
+    (let ((acc (list)))
+      (begin
+        (for-each
+          (fn (k)
+            (for-each
+              (fn (n)
+                (when (not (some (fn (m) (= m n)) acc))
+                  (set! acc (cons n acc))))
+              (hm-ftv-scheme (get env k))))
+          (keys env))
+        acc))))
+
+(define hm-apply (fn (subst t) (walk* t subst)))
+
+(define
+  hm-apply-scheme
+  (fn (subst s)
+    (let ((qs (hm-scheme-vars s))
+          (d {}))
+      (begin
+        (for-each
+          (fn (k)
+            (when (not (some (fn (q) (= q k)) qs))
+              (dict-set! d k (get subst k))))
+          (keys subst))
+        (hm-scheme qs (walk* (hm-scheme-type s) d))))))
+
+(define
+  hm-apply-env
+  (fn (subst env)
+    (let ((d {}))
+      (begin
+        (for-each
+          (fn (k) (dict-set! d k (hm-apply-scheme subst (get env k))))
+          (keys env))
+        d))))
+
+(define
+  hm-compose
+  (fn (s2 s1)
+    (let ((d {}))
+      (begin
+        (for-each (fn (k) (dict-set! d k (walk* (get s1 k) s2))) (keys s1))
+        (for-each
+          (fn (k) (when (not (has-key? d k)) (dict-set! d k (get s2 k))))
+          (keys s2))
+        d))))
+
+(define
+  hm-generalize
+  (fn (t env)
+    (let ((tvars (hm-ftv t))
+          (evars (hm-ftv-env env)))
+      (let ((qs (filter (fn (n) (not (some (fn (m) (= m n)) evars))) tvars)))
+        (hm-scheme qs t)))))
+
+(define
+  hm-instantiate
+  (fn (s counter)
+    (let ((qs (hm-scheme-vars s))
+          (subst {}))
+      (begin
+        (for-each
+          (fn (q) (set! subst (assoc subst q (hm-fresh-tv counter))))
+          qs)
+        (walk* (hm-scheme-type s) subst)))))
+
+;; Literal inference — the only AST kind whose typing rule is closed
+;; in the kit. Lambda / app / let live in host code so the host's own
+;; AST conventions stay untouched.
+(define
+  hm-infer-literal
+  (fn (expr)
+    (let ((v (ast-literal-value expr)))
+      (cond
+        ((number? v)  {:subst {} :type (hm-int)})
+        ((string? v)  {:subst {} :type (hm-string)})
+        ((boolean? v) {:subst {} :type (hm-bool)})
+        (:else (error (str "hm-infer-literal: unknown kind: " v)))))))
--- a/lib/guest/layout.sx
+++ b/lib/guest/layout.sx
@@ -0,0 +1,145 @@
+;; lib/guest/layout.sx — configurable off-side / layout-sensitive lexer.
+;;
+;; Inserts virtual open / close / separator tokens based on indentation.
+;; Configurable enough to encode either the Haskell 98 layout rule (let /
+;; where / do / of opens a virtual brace at the next token's column) or
+;; a Python-ish indent / dedent rule (a colon at the end of a line opens
+;; a block at the next non-blank line's column).
+;;
+;; Token shape (input + output)
+;; ----------------------------
+;; Each token is a dict {:type :value :line :col …}. The kit reads
+;; only :type / :value / :line / :col and passes everything else
+;; through. The input stream MUST be free of newline filler tokens
+;; (preprocess them away with your tokenizer) — line breaks are detected
+;; by comparing :line of consecutive tokens.
+;;
+;; Config
+;; ------
+;;   :open-keywords    list of strings; a token whose :value matches
+;;                     opens a new layout block at the next token's
+;;                     column (Haskell: let/where/do/of).
+;;   :open-trailing-fn (fn (tok) -> bool) — alternative trigger that
+;;                     fires AFTER the token is emitted. Use for
+;;                     Python-style trailing `:`.
+;;   :open-token / :close-token / :sep-token
+;;                     templates {:type :value} merged with :line and
+;;                     :col when virtual tokens are emitted.
+;;   :explicit-open?   (fn (tok) -> bool) — if the next token after a
+;;                     trigger satisfies this, suppress virtual layout
+;;                     for that block (Haskell: `{`).
+;;   :module-prelude?  if true, wrap whole input in an implicit block
+;;                     at the first token's column (Haskell yes,
+;;                     Python no).
+;;
+;; Public entry
+;; ------------
+;;   (layout-pass cfg tokens) -> tokens with virtual layout inserted.
+
+(define
+  layout-mk-virtual
+  (fn (template line col)
+    (assoc (assoc template :line line) :col col)))
+
+(define
+  layout-is-open-kw?
+  (fn (tok open-kws)
+    (and (= (get tok :type) "reserved")
+         (some (fn (k) (= k (get tok :value))) open-kws))))
+
+(define
+  layout-pass
+  (fn (cfg tokens)
+    (let ((open-kws (get cfg :open-keywords))
+          (trailing-fn (get cfg :open-trailing-fn))
+          (open-tmpl (get cfg :open-token))
+          (close-tmpl (get cfg :close-token))
+          (sep-tmpl (get cfg :sep-token))
+          (mod-prelude? (get cfg :module-prelude?))
+          (expl?-fn (get cfg :explicit-open?))
+          (out (list))
+          (stack (list))
+          (n (len tokens))
+          (i 0)
+          (prev-line -1)
+          (pending-open false)
+          (just-opened false))
+      (define
+        emit-closes-while-greater
+        (fn (col line)
+          (when (and (not (empty? stack)) (> (first stack) col))
+            (do
+              (append! out (layout-mk-virtual close-tmpl line col))
+              (set! stack (rest stack))
+              (emit-closes-while-greater col line)))))
+      (define
+        emit-pending-open
+        (fn (line col)
+          (do
+            (append! out (layout-mk-virtual open-tmpl line col))
+            (set! stack (cons col stack))
+            (set! pending-open false)
+            (set! just-opened true))))
+      (define
+        layout-step
+        (fn ()
+          (when (< i n)
+            (let ((tok (nth tokens i)))
+              (let ((line (get tok :line)) (col (get tok :col)))
+                (cond
+                  (pending-open
+                    (cond
+                      ((and (not (= expl?-fn nil)) (expl?-fn tok))
+                        (do
+                          (set! pending-open false)
+                          (append! out tok)
+                          (set! prev-line line)
+                          (set! i (+ i 1))
+                          (layout-step)))
+                      (:else
+                        (do
+                          (emit-pending-open line col)
+                          (layout-step)))))
+                  (:else
+                    (let ((on-fresh-line? (and (> prev-line 0) (> line prev-line))))
+                      (do
+                        (when on-fresh-line?
+                          (let ((stack-before stack))
+                            (begin
+                              (emit-closes-while-greater col line)
+                              (when (and (not (empty? stack))
+                                         (= (first stack) col)
+                                         (not just-opened)
+                                         ;; suppress separator if a dedent fired
+                                         ;; — the dedent is itself the separator
+                                         (= (len stack) (len stack-before)))
+                                (append! out (layout-mk-virtual sep-tmpl line col))))))
+                        (set! just-opened false)
+                        (append! out tok)
+                        (set! prev-line line)
+                        (set! i (+ i 1))
+                        (cond
+                          ((layout-is-open-kw? tok open-kws)
+                            (set! pending-open true))
+                          ((and (not (= trailing-fn nil)) (trailing-fn tok))
+                            (set! pending-open true)))
+                        (layout-step))))))))))
+      (begin
+        ;; Module prelude: implicit layout block at the first token's column.
+        (when (and mod-prelude? (> n 0))
+          (let ((tok (nth tokens 0)))
+            (do
+              (append! out (layout-mk-virtual open-tmpl (get tok :line) (get tok :col)))
+              (set! stack (cons (get tok :col) stack))
+              (set! just-opened true))))
+        (layout-step)
+        ;; EOF: close every remaining block.
+        (define close-rest
+          (fn ()
+            (when (not (empty? stack))
+              (do
+                (append! out (layout-mk-virtual close-tmpl 0 0))
+                (set! stack (rest stack))
+                (close-rest)))))
+        (close-rest)
+        out))))
--- a/lib/guest/tests/hm.sx
+++ b/lib/guest/tests/hm.sx
@@ -0,0 +1,89 @@
+;; lib/guest/tests/hm.sx — exercises lib/guest/hm.sx algebra.
+
+(define ghm-test-pass 0)
+(define ghm-test-fail 0)
+(define ghm-test-fails (list))
+
+(define
+  ghm-test
+  (fn (name actual expected)
+    (if (= actual expected)
+      (set! ghm-test-pass (+ ghm-test-pass 1))
+      (begin
+        (set! ghm-test-fail (+ ghm-test-fail 1))
+        (append! ghm-test-fails {:name name :expected expected :actual actual})))))
+
+;; ── Type constructors ─────────────────────────────────────────────
+(ghm-test "tv"           (hm-tv "a") (list :var "a"))
+(ghm-test "int"          (hm-int)    (list :ctor "Int" (list)))
+(ghm-test "arrow"        (ctor-head (hm-arrow (hm-int) (hm-bool))) "->")
+(ghm-test "arrow-args-len" (len (ctor-args (hm-arrow (hm-int) (hm-bool)))) 2)
+
+;; ── Schemes ───────────────────────────────────────────────────────
+(ghm-test "scheme-vars"  (hm-scheme-vars (hm-scheme (list "a") (hm-tv "a"))) (list "a"))
+(ghm-test "monotype-vars" (hm-scheme-vars (hm-monotype (hm-int))) (list))
+(ghm-test "scheme?-yes"  (hm-scheme? (hm-monotype (hm-int))) true)
+(ghm-test "scheme?-no"   (hm-scheme? (hm-int)) false)
+
+;; ── Fresh tyvars ──────────────────────────────────────────────────
+(ghm-test "fresh-1"
+  (let ((c (list 0))) (var-name (hm-fresh-tv c))) "t1")
+(ghm-test "fresh-bumps"
+  (let ((c (list 5))) (begin (hm-fresh-tv c) (first c))) 6)
+
+;; ── Free type variables ──────────────────────────────────────────
+(ghm-test "ftv-int"      (hm-ftv (hm-int)) (list))
+(ghm-test "ftv-tv"       (hm-ftv (hm-tv "a")) (list "a"))
+(ghm-test "ftv-arrow"
+  (len (hm-ftv (hm-arrow (hm-tv "a") (hm-arrow (hm-tv "b") (hm-tv "a"))))) 2)
+(ghm-test "ftv-scheme-quantified"
+  (hm-ftv-scheme (hm-scheme (list "a") (hm-arrow (hm-tv "a") (hm-tv "b")))) (list "b"))
+(ghm-test "ftv-env"
+  (let ((env (assoc {} "f" (hm-monotype (hm-arrow (hm-tv "x") (hm-tv "y"))))))
+    (len (hm-ftv-env env))) 2)
+
+;; ── Substitution / apply / compose ───────────────────────────────
+(ghm-test "apply-tv"
+  (hm-apply (assoc {} "a" (hm-int)) (hm-tv "a")) (hm-int))
+(ghm-test "apply-arrow"
+  (ctor-head
+    (hm-apply (assoc {} "a" (hm-int))
+              (hm-arrow (hm-tv "a") (hm-tv "b")))) "->")
+(ghm-test "compose-1-then-2"
+  (var-name
+    (hm-apply
+      (hm-compose (assoc {} "b" (hm-tv "c")) (assoc {} "a" (hm-tv "b")))
+      (hm-tv "a"))) "c")
+
+;; ── Generalize / Instantiate ─────────────────────────────────────
+;;   forall a. a -> a   instantiated twice yields fresh vars each time
+(ghm-test "generalize-id"
+  (len (hm-scheme-vars (hm-generalize (hm-arrow (hm-tv "a") (hm-tv "a")) {}))) 1)
+
+(ghm-test "generalize-skips-env"
+  ;; ftv(t)={a,b}, ftv(env)={a}, qs={b}
+  (let ((env (assoc {} "x" (hm-monotype (hm-tv "a")))))
+    (len (hm-scheme-vars
+           (hm-generalize (hm-arrow (hm-tv "a") (hm-tv "b")) env)))) 1)
+
+(ghm-test "instantiate-fresh"
+  (let ((s (hm-scheme (list "a") (hm-arrow (hm-tv "a") (hm-tv "a"))))
+        (c (list 0)))
+    (let ((t1 (hm-instantiate s c)) (t2 (hm-instantiate s c)))
+      (not (= (var-name (first (ctor-args t1)))
+              (var-name (first (ctor-args t2)))))))
+  true)
+
+;; ── Inference (literal only) ─────────────────────────────────────
+(ghm-test "infer-int"
+  (ctor-head (get (hm-infer-literal (ast-literal 42)) :type)) "Int")
+(ghm-test "infer-string"
+  (ctor-head (get (hm-infer-literal (ast-literal "hi")) :type)) "String")
+(ghm-test "infer-bool"
+  (ctor-head (get (hm-infer-literal (ast-literal true)) :type)) "Bool")
+
+(define ghm-tests-run!
+  (fn ()
+    {:passed ghm-test-pass
+     :failed ghm-test-fail
+     :total  (+ ghm-test-pass ghm-test-fail)}))
--- a/lib/guest/tests/layout.sx
+++ b/lib/guest/tests/layout.sx
@@ -0,0 +1,180 @@
+;; lib/guest/tests/layout.sx — synthetic Python-ish off-side fixture.
+;;
+;; Exercises lib/guest/layout.sx with a config different from Haskell's
+;; (no module-prelude, layout opens via trailing `:` not via reserved
+;; keyword) to prove the kit isn't Haskell-shaped.
+
+(define glayout-test-pass 0)
+(define glayout-test-fail 0)
+(define glayout-test-fails (list))
+
+(define
+  glayout-test
+  (fn (name actual expected)
+    (if (= actual expected)
+      (set! glayout-test-pass (+ glayout-test-pass 1))
+      (begin
+        (set! glayout-test-fail (+ glayout-test-fail 1))
+        (append! glayout-test-fails {:name name :expected expected :actual actual})))))
+
+;; Convenience: build a token from {type value line col}.
+(define
+  glayout-tok
+  (fn (ty val line col)
+    {:type ty :value val :line line :col col}))
+
+;; Project a token list to ((type value) ...) for compact comparison.
+(define
+  glayout-shape
+  (fn (toks)
+    (map (fn (t) (list (get t :type) (get t :value))) toks)))
+
+;; ── Haskell-flavour: keyword opens block ─────────────────────────
+(define
+  glayout-haskell-cfg
+  {:open-keywords (list "let" "where" "do" "of")
+   :open-trailing-fn nil
+   :open-token   {:type "vlbrace" :value "{"}
+   :close-token  {:type "vrbrace" :value "}"}
+   :sep-token    {:type "vsemi"   :value ";"}
+   :module-prelude? false
+   :explicit-open? (fn (tok) (= (get tok :type) "lbrace"))})
+
+;;   do
+;;     a
+;;     b
+;;   c       ← outside the do-block
+(glayout-test "haskell-do-block"
+  (glayout-shape
+    (layout-pass
+      glayout-haskell-cfg
+      (list (glayout-tok "reserved" "do" 1 1)
+            (glayout-tok "ident" "a" 2 3)
+            (glayout-tok "ident" "b" 3 3)
+            (glayout-tok "ident" "c" 4 1))))
+  (list (list "reserved" "do")
+        (list "vlbrace" "{")
+        (list "ident" "a")
+        (list "vsemi" ";")
+        (list "ident" "b")
+        (list "vrbrace" "}")
+        (list "ident" "c")))
+
+;; Explicit `{` after `do` suppresses virtual layout.
+(glayout-test "haskell-explicit-brace"
+  (glayout-shape
+    (layout-pass
+      glayout-haskell-cfg
+      (list (glayout-tok "reserved" "do" 1 1)
+            (glayout-tok "lbrace" "{" 1 4)
+            (glayout-tok "ident" "a" 1 6)
+            (glayout-tok "rbrace" "}" 1 8))))
+  (list (list "reserved" "do")
+        (list "lbrace" "{")
+        (list "ident" "a")
+        (list "rbrace" "}")))
+
+;; Single-statement do-block on the same line.
+(glayout-test "haskell-do-inline"
+  (glayout-shape
+    (layout-pass
+      glayout-haskell-cfg
+      (list (glayout-tok "reserved" "do" 1 1)
+            (glayout-tok "ident" "a" 1 4))))
+  (list (list "reserved" "do")
+        (list "vlbrace" "{")
+        (list "ident" "a")
+        (list "vrbrace" "}")))
+
+;; Module-prelude: wrap whole input in implicit layout block at first
+;; tok's column.
+(glayout-test "haskell-module-prelude"
+  (glayout-shape
+    (layout-pass
+      (assoc glayout-haskell-cfg :module-prelude? true)
+      (list (glayout-tok "ident" "x" 1 1)
+            (glayout-tok "ident" "y" 2 1)
+            (glayout-tok "ident" "z" 3 1))))
+  (list (list "vlbrace" "{")
+        (list "ident" "x")
+        (list "vsemi" ";")
+        (list "ident" "y")
+        (list "vsemi" ";")
+        (list "ident" "z")
+        (list "vrbrace" "}")))
+
+;; ── Python-flavour: trailing `:` opens block ─────────────────────
+(define
+  glayout-python-cfg
+  {:open-keywords (list)
+   :open-trailing-fn (fn (tok) (and (= (get tok :type) "punct")
+                                    (= (get tok :value) ":")))
+   :open-token   {:type "indent" :value "INDENT"}
+   :close-token  {:type "dedent" :value "DEDENT"}
+   :sep-token    {:type "newline" :value "NEWLINE"}
+   :module-prelude? false
+   :explicit-open? nil})
+
+;;   if x:
+;;       a
+;;       b
+;;   c
+(glayout-test "python-if-block"
+  (glayout-shape
+    (layout-pass
+      glayout-python-cfg
+      (list (glayout-tok "reserved" "if" 1 1)
+            (glayout-tok "ident" "x" 1 4)
+            (glayout-tok "punct" ":" 1 5)
+            (glayout-tok "ident" "a" 2 5)
+            (glayout-tok "ident" "b" 3 5)
+            (glayout-tok "ident" "c" 4 1))))
+  (list (list "reserved" "if")
+        (list "ident" "x")
+        (list "punct" ":")
+        (list "indent" "INDENT")
+        (list "ident" "a")
+        (list "newline" "NEWLINE")
+        (list "ident" "b")
+        (list "dedent" "DEDENT")
+        (list "ident" "c")))
+
+;; Nested Python-style blocks.
+;;   def f():
+;;       if x:
+;;           a
+;;       b
+(glayout-test "python-nested"
+  (glayout-shape
+    (layout-pass
+      glayout-python-cfg
+      (list (glayout-tok "reserved" "def" 1 1)
+            (glayout-tok "ident" "f" 1 5)
+            (glayout-tok "punct" "(" 1 6)
+            (glayout-tok "punct" ")" 1 7)
+            (glayout-tok "punct" ":" 1 8)
+            (glayout-tok "reserved" "if" 2 5)
+            (glayout-tok "ident" "x" 2 8)
+            (glayout-tok "punct" ":" 2 9)
+            (glayout-tok "ident" "a" 3 9)
+            (glayout-tok "ident" "b" 4 5))))
+  (list (list "reserved" "def")
+        (list "ident" "f")
+        (list "punct" "(")
+        (list "punct" ")")
+        (list "punct" ":")
+        (list "indent" "INDENT")
+        (list "reserved" "if")
+        (list "ident" "x")
+        (list "punct" ":")
+        (list "indent" "INDENT")
+        (list "ident" "a")
+        (list "dedent" "DEDENT")
+        (list "ident" "b")
+        (list "dedent" "DEDENT")))
+
+(define glayout-tests-run!
+  (fn ()
+    {:passed glayout-test-pass
+     :failed glayout-test-fail
+     :total  (+ glayout-test-pass glayout-test-fail)}))
--- a/lib/haskell/conformance.conf
+++ b/lib/haskell/conformance.conf
@@ -14,6 +14,8 @@ PRELOADS=(
  lib/haskell/runtime.sx
  lib/haskell/match.sx
  lib/haskell/eval.sx
+  lib/haskell/map.sx
+  lib/haskell/set.sx
  lib/haskell/testlib.sx
 )

@@ -36,6 +38,24 @@ SUITES=(
  "matrix:lib/haskell/tests/program-matrix.sx"
  "wordcount:lib/haskell/tests/program-wordcount.sx"
  "powers:lib/haskell/tests/program-powers.sx"
+  "caesar:lib/haskell/tests/program-caesar.sx"
+  "runlength-str:lib/haskell/tests/program-runlength-str.sx"
+  "showadt:lib/haskell/tests/program-showadt.sx"
+  "showio:lib/haskell/tests/program-showio.sx"
+  "partial:lib/haskell/tests/program-partial.sx"
+  "statistics:lib/haskell/tests/program-statistics.sx"
+  "newton:lib/haskell/tests/program-newton.sx"
+  "wordfreq:lib/haskell/tests/program-wordfreq.sx"
+  "mapgraph:lib/haskell/tests/program-mapgraph.sx"
+  "uniquewords:lib/haskell/tests/program-uniquewords.sx"
+  "setops:lib/haskell/tests/program-setops.sx"
+  "shapes:lib/haskell/tests/program-shapes.sx"
+  "person:lib/haskell/tests/program-person.sx"
+  "config:lib/haskell/tests/program-config.sx"
+  "counter:lib/haskell/tests/program-counter.sx"
+  "accumulate:lib/haskell/tests/program-accumulate.sx"
+  "safediv:lib/haskell/tests/program-safediv.sx"
+  "trycatch:lib/haskell/tests/program-trycatch.sx"
 )

 emit_scoreboard_json() {
--- a/lib/haskell/desugar.sx
+++ b/lib/haskell/desugar.sx
@@ -131,119 +131,281 @@
        (let
          ((tag (first node)))
          (cond
-            ;; Transformations
            ((= tag "where")
              (list
-                :let
-                (map hk-desugar (nth node 2))
+                :let (map hk-desugar (nth node 2))
                (hk-desugar (nth node 1))))
            ((= tag "guarded") (hk-guards-to-if (nth node 1)))
            ((= tag "list-comp")
-              (hk-lc-desugar
-                (hk-desugar (nth node 1))
-                (nth node 2)))
-
-            ;; Expression nodes
+              (hk-lc-desugar (hk-desugar (nth node 1)) (nth node 2)))
            ((= tag "app")
              (list
-                :app
-                (hk-desugar (nth node 1))
+                :app (hk-desugar (nth node 1))
                (hk-desugar (nth node 2))))
+            ((= tag "p-rec")
+              (let
+                ((cname (nth node 1))
+                  (field-pats (nth node 2))
+                  (field-order (hk-record-field-names cname)))
+                (cond
+                  ((nil? field-order)
+                    (raise (str "p-rec: no record info for " cname)))
+                  (:else
+                    (list
+                      :p-con
+                      cname
+                      (map
+                        (fn
+                          (fname)
+                          (let
+                            ((p (hk-find-rec-pair field-pats fname)))
+                            (cond
+                              ((nil? p) (list :p-wild))
+                              (:else (hk-desugar (nth p 1))))))
+                        field-order))))))
+            ((= tag "rec-update")
+              (list
+                :rec-update
+                (hk-desugar (nth node 1))
+                (map
+                  (fn (p) (list (first p) (hk-desugar (nth p 1))))
+                  (nth node 2))))
+            ((= tag "rec-create")
+              (let
+                ((cname (nth node 1))
+                  (field-pairs (nth node 2))
+                  (field-order (hk-record-field-names cname)))
+                (cond
+                  ((nil? field-order)
+                    (raise (str "rec-create: no record info for " cname)))
+                  (:else
+                    (let
+                      ((acc (list :con cname)))
+                      (begin
+                        (for-each
+                          (fn
+                            (fname)
+                            (let
+                              ((pair
+                                  (hk-find-rec-pair field-pairs fname)))
+                              (cond
+                                ((nil? pair)
+                                  (raise
+                                    (str
+                                      "rec-create: missing field "
+                                      fname
+                                      " for "
+                                      cname)))
+                                (:else
+                                  (set!
+                                    acc
+                                    (list
+                                      :app
+                                      acc
+                                      (hk-desugar (nth pair 1))))))))
+                          field-order)
+                        acc))))))
            ((= tag "op")
              (list
-                :op
-                (nth node 1)
+                :op (nth node 1)
                (hk-desugar (nth node 2))
                (hk-desugar (nth node 3))))
+            ((= tag "type-ann") (hk-desugar (nth node 1)))
            ((= tag "neg") (list :neg (hk-desugar (nth node 1))))
            ((= tag "if")
              (list
-                :if
-                (hk-desugar (nth node 1))
+                :if (hk-desugar (nth node 1))
                (hk-desugar (nth node 2))
                (hk-desugar (nth node 3))))
-            ((= tag "tuple")
-              (list :tuple (map hk-desugar (nth node 1))))
-            ((= tag "list")
-              (list :list (map hk-desugar (nth node 1))))
+            ((= tag "tuple") (list :tuple (map hk-desugar (nth node 1))))
+            ((= tag "list") (list :list (map hk-desugar (nth node 1))))
            ((= tag "range")
              (list
-                :range
-                (hk-desugar (nth node 1))
+                :range (hk-desugar (nth node 1))
                (hk-desugar (nth node 2))))
            ((= tag "range-step")
              (list
-                :range-step
-                (hk-desugar (nth node 1))
+                :range-step (hk-desugar (nth node 1))
                (hk-desugar (nth node 2))
                (hk-desugar (nth node 3))))
            ((= tag "lambda")
-              (list
-                :lambda
-                (nth node 1)
-                (hk-desugar (nth node 2))))
+              (list :lambda (nth node 1) (hk-desugar (nth node 2))))
            ((= tag "let")
              (list
-                :let
-                (map hk-desugar (nth node 1))
+                :let (map hk-desugar (nth node 1))
                (hk-desugar (nth node 2))))
            ((= tag "case")
              (list
-                :case
-                (hk-desugar (nth node 1))
+                :case (hk-desugar (nth node 1))
                (map hk-desugar (nth node 2))))
            ((= tag "alt")
-              (list :alt (nth node 1) (hk-desugar (nth node 2))))
+              (list :alt (hk-desugar (nth node 1)) (hk-desugar (nth node 2))))
            ((= tag "do") (hk-desugar-do (nth node 1)))
            ((= tag "sect-left")
-              (list
-                :sect-left
-                (nth node 1)
-                (hk-desugar (nth node 2))))
+              (list :sect-left (nth node 1) (hk-desugar (nth node 2))))
            ((= tag "sect-right")
-              (list
-                :sect-right
-                (nth node 1)
-                (hk-desugar (nth node 2))))
-
-            ;; Top-level
+              (list :sect-right (nth node 1) (hk-desugar (nth node 2))))
            ((= tag "program")
-              (list :program (map hk-desugar (nth node 1))))
+              (list :program (map hk-desugar (hk-expand-records (nth node 1)))))
            ((= tag "module")
              (list
-                :module
-                (nth node 1)
+                :module (nth node 1)
                (nth node 2)
                (nth node 3)
-                (map hk-desugar (nth node 4))))
-
-            ;; Decls carrying a body
+                (map hk-desugar (hk-expand-records (nth node 4)))))
            ((= tag "fun-clause")
              (list
-                :fun-clause
-                (nth node 1)
-                (nth node 2)
+                :fun-clause (nth node 1)
+                (map hk-desugar (nth node 2))
                (hk-desugar (nth node 3))))
+            ((= tag "instance-decl")
+              (list
+                :instance-decl (nth node 1)
+                (nth node 2)
+                (map hk-desugar (nth node 3))))
            ((= tag "pat-bind")
-              (list
-                :pat-bind
-                (nth node 1)
-                (hk-desugar (nth node 2))))
+              (list :pat-bind (nth node 1) (hk-desugar (nth node 2))))
            ((= tag "bind")
-              (list
-                :bind
-                (nth node 1)
-                (hk-desugar (nth node 2))))
-
-            ;; Everything else: leaf literals, vars, cons, patterns,
-            ;; types, imports, type-sigs, data / newtype / fixity, …
+              (list :bind (nth node 1) (hk-desugar (nth node 2))))
            (:else node)))))))

 ;; Convenience — tokenize + layout + parse + desugar.
-(define
-  hk-core
-  (fn (src) (hk-desugar (hk-parse-top src))))
+(define hk-record-fields (dict))

 (define
-  hk-core-expr
-  (fn (src) (hk-desugar (hk-parse src))))
+  hk-register-record-fields!
+  (fn (cname fields) (dict-set! hk-record-fields cname fields)))
+
+(define
+  hk-record-field-names
+  (fn
+    (cname)
+    (if (has-key? hk-record-fields cname) (get hk-record-fields cname) nil)))
+
+(define
+  hk-record-field-index
+  (fn
+    (cname fname)
+    (let
+      ((fields (hk-record-field-names cname)))
+      (cond
+        ((nil? fields) -1)
+        (:else
+          (let
+            ((i 0) (idx -1))
+            (begin
+              (for-each
+                (fn
+                  (f)
+                  (begin (when (= f fname) (set! idx i)) (set! i (+ i 1))))
+                fields)
+              idx)))))))
+
+(define
+  hk-find-rec-pair
+  (fn
+    (pairs name)
+    (cond
+      ((empty? pairs) nil)
+      ((= (first (first pairs)) name) (first pairs))
+      (:else (hk-find-rec-pair (rest pairs) name)))))
+
+(define
+  hk-record-accessors
+  (fn
+    (cname rec-fields)
+    (let
+      ((n (len rec-fields)) (i 0) (out (list)))
+      (define
+        hk-ra-loop
+        (fn
+          ()
+          (when
+            (< i n)
+            (let
+              ((field (nth rec-fields i)))
+              (let
+                ((fname (first field)) (j 0) (pats (list)))
+                (define
+                  hk-pat-loop
+                  (fn
+                    ()
+                    (when
+                      (< j n)
+                      (begin
+                        (append!
+                          pats
+                          (if
+                            (= j i)
+                            (list "p-var" "__rec_field")
+                            (list "p-wild")))
+                        (set! j (+ j 1))
+                        (hk-pat-loop)))))
+                (hk-pat-loop)
+                (append!
+                  out
+                  (list
+                    "fun-clause"
+                    fname
+                    (list (list "p-con" cname pats))
+                    (list "var" "__rec_field")))
+                (set! i (+ i 1))
+                (hk-ra-loop))))))
+      (hk-ra-loop)
+      out)))
+
+(define
+  hk-expand-records
+  (fn
+    (decls)
+    (let
+      ((out (list)))
+      (for-each
+        (fn
+          (d)
+          (cond
+            ((and (list? d) (= (first d) "data"))
+              (let
+                ((dname (nth d 1))
+                  (tvars (nth d 2))
+                  (cons-list (nth d 3))
+                  (deriving (if (> (len d) 4) (nth d 4) (list)))
+                  (new-cons (list))
+                  (accessors (list)))
+                (begin
+                  (for-each
+                    (fn
+                      (c)
+                      (cond
+                        ((= (first c) "con-rec")
+                          (let
+                            ((cname (nth c 1)) (rec-fields (nth c 2)))
+                            (begin
+                              (hk-register-record-fields!
+                                cname
+                                (map (fn (f) (first f)) rec-fields))
+                              (append!
+                                new-cons
+                                (list
+                                  "con-def"
+                                  cname
+                                  (map (fn (f) (nth f 1)) rec-fields)))
+                              (for-each
+                                (fn (a) (append! accessors a))
+                                (hk-record-accessors cname rec-fields)))))
+                        (:else (append! new-cons c))))
+                    cons-list)
+                  (append!
+                    out
+                    (if
+                      (empty? deriving)
+                      (list "data" dname tvars new-cons)
+                      (list "data" dname tvars new-cons deriving)))
+                  (for-each (fn (a) (append! out a)) accessors))))
+            (:else (append! out d))))
+        decls)
+      out)))
+
+(define hk-core (fn (src) (hk-desugar (hk-parse-top src))))
+
+(define hk-core-expr (fn (src) (hk-desugar (hk-parse src))))
--- a/lib/haskell/eval.sx
+++ b/lib/haskell/eval.sx
--- a/lib/haskell/map.sx
+++ b/lib/haskell/map.sx
@@ -0,0 +1,520 @@
+;; map.sx — Phase 11 Data.Map: weight-balanced BST in pure SX.
+;;
+;; Algorithm: Adams's weight-balanced tree (the same family as Haskell's
+;; Data.Map). Each node tracks its size; rotations maintain the invariant
+;;
+;;     size(small-side) * delta >= size(large-side)        (delta = 3)
+;;
+;; with single or double rotations chosen by the gamma ratio (gamma = 2).
+;; The size field is an Int and is included so `size`, `lookup`, etc. are
+;; O(log n) on both extremes of the tree.
+;;
+;; Representation:
+;;   Empty → ("Map-Empty")
+;;   Node  → ("Map-Node" key val left right size)
+;;
+;; All operations are pure SX — no mutation of nodes once constructed.
+;; The user-facing Haskell layer (Phase 11 next iteration) wraps these
+;; for `import Data.Map as Map`.
+
+;; ── Constructors ────────────────────────────────────────────
+(define hk-map-empty (list "Map-Empty"))
+
+(define
+  hk-map-node
+  (fn
+    (k v l r)
+    (list "Map-Node" k v l r (+ 1 (+ (hk-map-size l) (hk-map-size r))))))
+
+;; ── Predicates and accessors ────────────────────────────────
+(define hk-map-empty? (fn (m) (and (list? m) (= (first m) "Map-Empty"))))
+
+(define hk-map-node? (fn (m) (and (list? m) (= (first m) "Map-Node"))))
+
+(define
+  hk-map-size
+  (fn (m) (cond ((hk-map-empty? m) 0) (:else (nth m 5)))))
+
+(define hk-map-key (fn (m) (nth m 1)))
+(define hk-map-val (fn (m) (nth m 2)))
+(define hk-map-left (fn (m) (nth m 3)))
+(define hk-map-right (fn (m) (nth m 4)))
+
+;; ── Weight-balanced rotations ───────────────────────────────
+;; delta and gamma per Adams 1992 / Haskell Data.Map.
+
+(define hk-map-delta 3)
+(define hk-map-gamma 2)
+
+(define
+  hk-map-single-l
+  (fn
+    (k v l r)
+    (let
+      ((rk (hk-map-key r))
+        (rv (hk-map-val r))
+        (rl (hk-map-left r))
+        (rr (hk-map-right r)))
+      (hk-map-node rk rv (hk-map-node k v l rl) rr))))
+
+(define
+  hk-map-single-r
+  (fn
+    (k v l r)
+    (let
+      ((lk (hk-map-key l))
+        (lv (hk-map-val l))
+        (ll (hk-map-left l))
+        (lr (hk-map-right l)))
+      (hk-map-node lk lv ll (hk-map-node k v lr r)))))
+
+(define
+  hk-map-double-l
+  (fn
+    (k v l r)
+    (let
+      ((rk (hk-map-key r))
+        (rv (hk-map-val r))
+        (rl (hk-map-left r))
+        (rr (hk-map-right r))
+        (rlk (hk-map-key (hk-map-left r)))
+        (rlv (hk-map-val (hk-map-left r)))
+        (rll (hk-map-left (hk-map-left r)))
+        (rlr (hk-map-right (hk-map-left r))))
+      (hk-map-node
+        rlk
+        rlv
+        (hk-map-node k v l rll)
+        (hk-map-node rk rv rlr rr)))))
+
+(define
+  hk-map-double-r
+  (fn
+    (k v l r)
+    (let
+      ((lk (hk-map-key l))
+        (lv (hk-map-val l))
+        (ll (hk-map-left l))
+        (lr (hk-map-right l))
+        (lrk (hk-map-key (hk-map-right l)))
+        (lrv (hk-map-val (hk-map-right l)))
+        (lrl (hk-map-left (hk-map-right l)))
+        (lrr (hk-map-right (hk-map-right l))))
+      (hk-map-node
+        lrk
+        lrv
+        (hk-map-node lk lv ll lrl)
+        (hk-map-node k v lrr r)))))
+
+;; ── Balanced node constructor ──────────────────────────────
+;; Use this in place of hk-map-node when one side may have grown
+;; or shrunk by one and we need to restore the weight invariant.
+(define
+  hk-map-balance
+  (fn
+    (k v l r)
+    (let
+      ((sl (hk-map-size l)) (sr (hk-map-size r)))
+      (cond
+        ((<= (+ sl sr) 1) (hk-map-node k v l r))
+        ((> sr (* hk-map-delta sl))
+          (let
+            ((rl (hk-map-left r)) (rr (hk-map-right r)))
+            (cond
+              ((< (hk-map-size rl) (* hk-map-gamma (hk-map-size rr)))
+                (hk-map-single-l k v l r))
+              (:else (hk-map-double-l k v l r)))))
+        ((> sl (* hk-map-delta sr))
+          (let
+            ((ll (hk-map-left l)) (lr (hk-map-right l)))
+            (cond
+              ((< (hk-map-size lr) (* hk-map-gamma (hk-map-size ll)))
+                (hk-map-single-r k v l r))
+              (:else (hk-map-double-r k v l r)))))
+        (:else (hk-map-node k v l r))))))
+
+(define
+  hk-map-singleton
+  (fn (k v) (hk-map-node k v hk-map-empty hk-map-empty)))
+
+(define
+  hk-map-insert
+  (fn
+    (k v m)
+    (cond
+      ((hk-map-empty? m) (hk-map-singleton k v))
+      (:else
+        (let
+          ((mk (hk-map-key m)))
+          (cond
+            ((< k mk)
+              (hk-map-balance
+                mk
+                (hk-map-val m)
+                (hk-map-insert k v (hk-map-left m))
+                (hk-map-right m)))
+            ((> k mk)
+              (hk-map-balance
+                mk
+                (hk-map-val m)
+                (hk-map-left m)
+                (hk-map-insert k v (hk-map-right m))))
+            (:else (hk-map-node k v (hk-map-left m) (hk-map-right m)))))))))
+
+(define
+  hk-map-lookup
+  (fn
+    (k m)
+    (cond
+      ((hk-map-empty? m) (list "Nothing"))
+      (:else
+        (let
+          ((mk (hk-map-key m)))
+          (cond
+            ((< k mk) (hk-map-lookup k (hk-map-left m)))
+            ((> k mk) (hk-map-lookup k (hk-map-right m)))
+            (:else (list "Just" (hk-map-val m)))))))))
+
+(define
+  hk-map-member
+  (fn
+    (k m)
+    (cond
+      ((hk-map-empty? m) false)
+      (:else
+        (let
+          ((mk (hk-map-key m)))
+          (cond
+            ((< k mk) (hk-map-member k (hk-map-left m)))
+            ((> k mk) (hk-map-member k (hk-map-right m)))
+            (:else true)))))))
+
+(define hk-map-null hk-map-empty?)
+
+(define
+  hk-map-find-min
+  (fn
+    (m)
+    (cond
+      ((hk-map-empty? (hk-map-left m))
+        (list (hk-map-key m) (hk-map-val m)))
+      (:else (hk-map-find-min (hk-map-left m))))))
+
+(define
+  hk-map-delete-min
+  (fn
+    (m)
+    (cond
+      ((hk-map-empty? (hk-map-left m)) (hk-map-right m))
+      (:else
+        (hk-map-balance
+          (hk-map-key m)
+          (hk-map-val m)
+          (hk-map-delete-min (hk-map-left m))
+          (hk-map-right m))))))
+
+(define
+  hk-map-find-max
+  (fn
+    (m)
+    (cond
+      ((hk-map-empty? (hk-map-right m))
+        (list (hk-map-key m) (hk-map-val m)))
+      (:else (hk-map-find-max (hk-map-right m))))))
+
+(define
+  hk-map-delete-max
+  (fn
+    (m)
+    (cond
+      ((hk-map-empty? (hk-map-right m)) (hk-map-left m))
+      (:else
+        (hk-map-balance
+          (hk-map-key m)
+          (hk-map-val m)
+          (hk-map-left m)
+          (hk-map-delete-max (hk-map-right m)))))))
+
+(define
+  hk-map-glue
+  (fn
+    (l r)
+    (cond
+      ((hk-map-empty? l) r)
+      ((hk-map-empty? r) l)
+      ((> (hk-map-size l) (hk-map-size r))
+        (let
+          ((mp (hk-map-find-max l)))
+          (hk-map-balance (first mp) (nth mp 1) (hk-map-delete-max l) r)))
+      (:else
+        (let
+          ((mp (hk-map-find-min r)))
+          (hk-map-balance (first mp) (nth mp 1) l (hk-map-delete-min r)))))))
+
+(define
+  hk-map-delete
+  (fn
+    (k m)
+    (cond
+      ((hk-map-empty? m) m)
+      (:else
+        (let
+          ((mk (hk-map-key m)))
+          (cond
+            ((< k mk)
+              (hk-map-balance
+                mk
+                (hk-map-val m)
+                (hk-map-delete k (hk-map-left m))
+                (hk-map-right m)))
+            ((> k mk)
+              (hk-map-balance
+                mk
+                (hk-map-val m)
+                (hk-map-left m)
+                (hk-map-delete k (hk-map-right m))))
+            (:else (hk-map-glue (hk-map-left m) (hk-map-right m)))))))))
+
+(define
+  hk-map-from-list
+  (fn
+    (pairs)
+    (reduce
+      (fn (acc p) (hk-map-insert (first p) (nth p 1) acc))
+      hk-map-empty
+      pairs)))
+
+(define
+  hk-map-to-asc-list
+  (fn
+    (m)
+    (cond
+      ((hk-map-empty? m) (list))
+      (:else
+        (append
+          (hk-map-to-asc-list (hk-map-left m))
+          (cons
+            (list (hk-map-key m) (hk-map-val m))
+            (hk-map-to-asc-list (hk-map-right m))))))))
+
+(define hk-map-to-list hk-map-to-asc-list)
+
+(define
+  hk-map-keys
+  (fn
+    (m)
+    (cond
+      ((hk-map-empty? m) (list))
+      (:else
+        (append
+          (hk-map-keys (hk-map-left m))
+          (cons (hk-map-key m) (hk-map-keys (hk-map-right m))))))))
+
+(define
+  hk-map-elems
+  (fn
+    (m)
+    (cond
+      ((hk-map-empty? m) (list))
+      (:else
+        (append
+          (hk-map-elems (hk-map-left m))
+          (cons (hk-map-val m) (hk-map-elems (hk-map-right m))))))))
+
+(define
+  hk-map-union-with
+  (fn
+    (f m1 m2)
+    (reduce
+      (fn
+        (acc p)
+        (let
+          ((k (first p)) (v (nth p 1)))
+          (let
+            ((look (hk-map-lookup k acc)))
+            (cond
+              ((= (first look) "Just")
+                (hk-map-insert k (f (nth look 1) v) acc))
+              (:else (hk-map-insert k v acc))))))
+      m1
+      (hk-map-to-asc-list m2))))
+
+(define
+  hk-map-intersection-with
+  (fn
+    (f m1 m2)
+    (reduce
+      (fn
+        (acc p)
+        (let
+          ((k (first p)) (v1 (nth p 1)))
+          (let
+            ((look (hk-map-lookup k m2)))
+            (cond
+              ((= (first look) "Just")
+                (hk-map-insert k (f v1 (nth look 1)) acc))
+              (:else acc)))))
+      hk-map-empty
+      (hk-map-to-asc-list m1))))
+
+(define
+  hk-map-difference
+  (fn
+    (m1 m2)
+    (reduce
+      (fn
+        (acc p)
+        (let
+          ((k (first p)) (v (nth p 1)))
+          (cond ((hk-map-member k m2) acc) (:else (hk-map-insert k v acc)))))
+      hk-map-empty
+      (hk-map-to-asc-list m1))))
+
+(define
+  hk-map-foldl-with-key
+  (fn
+    (f acc m)
+    (cond
+      ((hk-map-empty? m) acc)
+      (:else
+        (let
+          ((acc1 (hk-map-foldl-with-key f acc (hk-map-left m))))
+          (let
+            ((acc2 (f acc1 (hk-map-key m) (hk-map-val m))))
+            (hk-map-foldl-with-key f acc2 (hk-map-right m))))))))
+
+(define
+  hk-map-foldr-with-key
+  (fn
+    (f acc m)
+    (cond
+      ((hk-map-empty? m) acc)
+      (:else
+        (let
+          ((acc1 (hk-map-foldr-with-key f acc (hk-map-right m))))
+          (let
+            ((acc2 (f (hk-map-key m) (hk-map-val m) acc1)))
+            (hk-map-foldr-with-key f acc2 (hk-map-left m))))))))
+
+(define
+  hk-map-map-with-key
+  (fn
+    (f m)
+    (cond
+      ((hk-map-empty? m) m)
+      (:else
+        (list
+          "Map-Node"
+          (hk-map-key m)
+          (f (hk-map-key m) (hk-map-val m))
+          (hk-map-map-with-key f (hk-map-left m))
+          (hk-map-map-with-key f (hk-map-right m))
+          (hk-map-size m))))))
+
+(define
+  hk-map-filter-with-key
+  (fn
+    (p m)
+    (hk-map-foldr-with-key
+      (fn (k v acc) (cond ((p k v) (hk-map-insert k v acc)) (:else acc)))
+      hk-map-empty
+      m)))
+
+(define
+  hk-map-adjust
+  (fn
+    (f k m)
+    (cond
+      ((hk-map-empty? m) m)
+      (:else
+        (let
+          ((mk (hk-map-key m)))
+          (cond
+            ((< k mk)
+              (hk-map-node
+                mk
+                (hk-map-val m)
+                (hk-map-adjust f k (hk-map-left m))
+                (hk-map-right m)))
+            ((> k mk)
+              (hk-map-node
+                mk
+                (hk-map-val m)
+                (hk-map-left m)
+                (hk-map-adjust f k (hk-map-right m))))
+            (:else
+              (hk-map-node
+                mk
+                (f (hk-map-val m))
+                (hk-map-left m)
+                (hk-map-right m)))))))))
+
+(define
+  hk-map-insert-with
+  (fn
+    (f k v m)
+    (cond
+      ((hk-map-empty? m) (hk-map-singleton k v))
+      (:else
+        (let
+          ((mk (hk-map-key m)))
+          (cond
+            ((< k mk)
+              (hk-map-balance
+                mk
+                (hk-map-val m)
+                (hk-map-insert-with f k v (hk-map-left m))
+                (hk-map-right m)))
+            ((> k mk)
+              (hk-map-balance
+                mk
+                (hk-map-val m)
+                (hk-map-left m)
+                (hk-map-insert-with f k v (hk-map-right m))))
+            (:else
+              (hk-map-node
+                mk
+                (f v (hk-map-val m))
+                (hk-map-left m)
+                (hk-map-right m)))))))))
+
+(define
+  hk-map-insert-with-key
+  (fn
+    (f k v m)
+    (cond
+      ((hk-map-empty? m) (hk-map-singleton k v))
+      (:else
+        (let
+          ((mk (hk-map-key m)))
+          (cond
+            ((< k mk)
+              (hk-map-balance
+                mk
+                (hk-map-val m)
+                (hk-map-insert-with-key f k v (hk-map-left m))
+                (hk-map-right m)))
+            ((> k mk)
+              (hk-map-balance
+                mk
+                (hk-map-val m)
+                (hk-map-left m)
+                (hk-map-insert-with-key f k v (hk-map-right m))))
+            (:else
+              (hk-map-node
+                mk
+                (f k v (hk-map-val m))
+                (hk-map-left m)
+                (hk-map-right m)))))))))
+
+(define
+  hk-map-alter
+  (fn
+    (f k m)
+    (let
+      ((look (hk-map-lookup k m)))
+      (let
+        ((res (f look)))
+        (cond
+          ((= (first res) "Nothing") (hk-map-delete k m))
+          (:else (hk-map-insert k (nth res 1) m)))))))
--- a/lib/haskell/match.sx
+++ b/lib/haskell/match.sx
@@ -87,45 +87,41 @@
                  ((nil? res) nil)
                  (:else (assoc res (nth pat 1) val)))))
            (:else
-              (let ((fv (hk-force val)))
+              (let
+                ((fv (hk-force val)))
                (cond
                  ((= tag "p-int")
-                    (if
-                      (and (number? fv) (= fv (nth pat 1)))
-                      env
-                      nil))
+                    (if (and (number? fv) (= fv (nth pat 1))) env nil))
                  ((= tag "p-float")
-                    (if
-                      (and (number? fv) (= fv (nth pat 1)))
-                      env
-                      nil))
+                    (if (and (number? fv) (= fv (nth pat 1))) env nil))
                  ((= tag "p-string")
-                    (if
-                      (and (string? fv) (= fv (nth pat 1)))
-                      env
-                      nil))
+                    (if (and (string? fv) (= fv (nth pat 1))) env nil))
                  ((= tag "p-char")
-                    (if
-                      (and (string? fv) (= fv (nth pat 1)))
-                      env
-                      nil))
+                    (if (and (string? fv) (= fv (nth pat 1))) env nil))
                  ((= tag "p-con")
                    (let
                      ((pat-name (nth pat 1)) (pat-args (nth pat 2)))
                      (cond
+                        ((and (= pat-name ":") (hk-str? fv) (not (hk-str-null? fv)))
+                          (let
+                            ((str-head (hk-str-head fv))
+                              (str-tail (hk-str-tail fv)))
+                            (let
+                              ((head-pat (nth pat-args 0))
+                                (tail-pat (nth pat-args 1)))
+                              (let
+                                ((res (hk-match head-pat str-head env)))
+                                (cond
+                                  ((nil? res) nil)
+                                  (:else (hk-match tail-pat str-tail res)))))))
                        ((not (hk-is-con-val? fv)) nil)
                        ((not (= (hk-val-con-name fv) pat-name)) nil)
                        (:else
                          (let
                            ((val-args (hk-val-con-args fv)))
                            (cond
-                              ((not (= (len pat-args) (len val-args)))
-                                nil)
-                              (:else
-                                (hk-match-all
-                                  pat-args
-                                  val-args
-                                  env))))))))
+                              ((not (= (len val-args) (len pat-args))) nil)
+                              (:else (hk-match-all pat-args val-args env))))))))
                  ((= tag "p-tuple")
                    (let
                      ((items (nth pat 1)))
@@ -134,13 +130,8 @@
                        ((not (= (hk-val-con-name fv) "Tuple")) nil)
                        ((not (= (len (hk-val-con-args fv)) (len items)))
                          nil)
-                        (:else
-                          (hk-match-all
-                            items
-                            (hk-val-con-args fv)
-                            env)))))
-                  ((= tag "p-list")
-                    (hk-match-list-pat (nth pat 1) fv env))
+                        (:else (hk-match-all items (hk-val-con-args fv) env)))))
+                  ((= tag "p-list") (hk-match-list-pat (nth pat 1) fv env))
                  (:else nil))))))))))

 (define
@@ -161,17 +152,26 @@
  hk-match-list-pat
  (fn
    (items val env)
-    (let ((fv (hk-force val)))
+    (let
+      ((fv (hk-force val)))
      (cond
        ((empty? items)
          (if
-            (and
-              (hk-is-con-val? fv)
-              (= (hk-val-con-name fv) "[]"))
+            (or
+              (and (hk-is-con-val? fv) (= (hk-val-con-name fv) "[]"))
+              (and (hk-str? fv) (hk-str-null? fv)))
            env
            nil))
        (:else
          (cond
+            ((and (hk-str? fv) (not (hk-str-null? fv)))
+              (let
+                ((h (hk-str-head fv)) (t (hk-str-tail fv)))
+                (let
+                  ((res (hk-match (first items) h env)))
+                  (cond
+                    ((nil? res) nil)
+                    (:else (hk-match-list-pat (rest items) t res))))))
            ((not (hk-is-con-val? fv)) nil)
            ((not (= (hk-val-con-name fv) ":")) nil)
            (:else
@@ -183,11 +183,7 @@
                    ((res (hk-match (first items) h env)))
                    (cond
                      ((nil? res) nil)
-                      (:else
-                        (hk-match-list-pat
-                          (rest items)
-                          t
-                          res)))))))))))))
+                      (:else (hk-match-list-pat (rest items) t res)))))))))))))

 ;; ── Convenience: parse a pattern from source for tests ─────
 ;; (Uses the parser's case-alt entry — `case _ of pat -> 0` —
--- a/lib/haskell/parser.sx
+++ b/lib/haskell/parser.sx
@@ -208,9 +208,19 @@
              ((= (get t "type") "char")
                (do (hk-advance!) (list :char (get t "value"))))
              ((= (get t "type") "varid")
-                (do (hk-advance!) (list :var (get t "value"))))
+                (do
+                  (hk-advance!)
+                  (cond
+                    ((hk-match? "lbrace" nil)
+                      (hk-parse-rec-update (list :var (get t "value"))))
+                    (:else (list :var (get t "value"))))))
              ((= (get t "type") "conid")
-                (do (hk-advance!) (list :con (get t "value"))))
+                (do
+                  (hk-advance!)
+                  (cond
+                    ((hk-match? "lbrace" nil)
+                      (hk-parse-rec-create (get t "value")))
+                    (:else (list :con (get t "value"))))))
              ((= (get t "type") "qvarid")
                (do (hk-advance!) (list :var (get t "value"))))
              ((= (get t "type") "qconid")
@@ -265,38 +275,47 @@
                            (list :sect-right op-name expr-e))))))
                  (:else
                    (let
-                      ((first-e (hk-parse-expr-inner))
-                        (items (list))
-                        (is-tuple false))
-                      (append! items first-e)
-                      (define
-                        hk-tup-loop
-                        (fn
-                          ()
-                          (when
-                            (hk-match? "comma" nil)
-                            (do
-                              (hk-advance!)
-                              (set! is-tuple true)
-                              (append! items (hk-parse-expr-inner))
-                              (hk-tup-loop)))))
-                      (hk-tup-loop)
+                      ((first-e (hk-parse-expr-inner)))
                      (cond
-                        ((hk-match? "rparen" nil)
+                        ((hk-match? "reservedop" "::")
                          (do
                            (hk-advance!)
-                            (if is-tuple (list :tuple items) first-e)))
+                            (let
+                              ((ann-type (hk-parse-type)))
+                              (hk-expect! "rparen" nil)
+                              (list :type-ann first-e ann-type))))
                        (:else
                          (let
-                            ((op-info2 (hk-section-op-info)))
+                            ((items (list)) (is-tuple false))
+                            (append! items first-e)
+                            (define
+                              hk-tup-loop
+                              (fn
+                                ()
+                                (when
+                                  (hk-match? "comma" nil)
+                                  (do
+                                    (hk-advance!)
+                                    (set! is-tuple true)
+                                    (append! items (hk-parse-expr-inner))
+                                    (hk-tup-loop)))))
+                            (hk-tup-loop)
                            (cond
-                              ((and (not (nil? op-info2)) (not is-tuple) (let ((after2 (hk-peek-at (get op-info2 "len")))) (and (not (nil? after2)) (= (get after2 "type") "rparen"))))
-                                (let
-                                  ((op-name (get op-info2 "name")))
-                                  (hk-consume-op!)
+                              ((hk-match? "rparen" nil)
+                                (do
                                  (hk-advance!)
-                                  (list :sect-left op-name first-e)))
-                              (:else (hk-err "expected ')' after expression"))))))))))))))
+                                  (if is-tuple (list :tuple items) first-e)))
+                              (:else
+                                (let
+                                  ((op-info2 (hk-section-op-info)))
+                                  (cond
+                                    ((and (not (nil? op-info2)) (not is-tuple) (let ((after2 (hk-peek-at (get op-info2 "len")))) (and (not (nil? after2)) (= (get after2 "type") "rparen"))))
+                                      (let
+                                        ((op-name (get op-info2 "name")))
+                                        (hk-consume-op!)
+                                        (hk-advance!)
+                                        (list :sect-left op-name first-e)))
+                                    (:else (hk-err "expected ')' after expression")))))))))))))))))
      (define
        hk-comp-qual-is-gen?
        (fn
@@ -456,6 +475,90 @@
                    (do
                      (hk-expect! "rbracket" nil)
                      (list :list (list first-e))))))))))
+      (define
+        hk-parse-rec-create
+        (fn
+          (cname)
+          (begin
+            (hk-expect! "lbrace" nil)
+            (let
+              ((fields (list)))
+              (define
+                hk-rc-loop
+                (fn
+                  ()
+                  (when
+                    (hk-match? "varid" nil)
+                    (let
+                      ((fname (get (hk-advance!) "value")))
+                      (begin
+                        (hk-expect! "reservedop" "=")
+                        (let
+                          ((fexpr (hk-parse-expr-inner)))
+                          (begin
+                            (append! fields (list fname fexpr))
+                            (when
+                              (hk-match? "comma" nil)
+                              (begin (hk-advance!) (hk-rc-loop))))))))))
+              (hk-rc-loop)
+              (hk-expect! "rbrace" nil)
+              (list :rec-create cname fields)))))
+      (define
+        hk-parse-rec-update
+        (fn
+          (rec-expr)
+          (begin
+            (hk-expect! "lbrace" nil)
+            (let
+              ((fields (list)))
+              (define
+                hk-ru-loop
+                (fn
+                  ()
+                  (when
+                    (hk-match? "varid" nil)
+                    (let
+                      ((fname (get (hk-advance!) "value")))
+                      (begin
+                        (hk-expect! "reservedop" "=")
+                        (let
+                          ((fexpr (hk-parse-expr-inner)))
+                          (begin
+                            (append! fields (list fname fexpr))
+                            (when
+                              (hk-match? "comma" nil)
+                              (begin (hk-advance!) (hk-ru-loop))))))))))
+              (hk-ru-loop)
+              (hk-expect! "rbrace" nil)
+              (list :rec-update rec-expr fields)))))
+      (define
+        hk-parse-rec-pat
+        (fn
+          (cname)
+          (begin
+            (hk-expect! "lbrace" nil)
+            (let
+              ((field-pats (list)))
+              (define
+                hk-rp-loop
+                (fn
+                  ()
+                  (when
+                    (hk-match? "varid" nil)
+                    (let
+                      ((fname (get (hk-advance!) "value")))
+                      (begin
+                        (hk-expect! "reservedop" "=")
+                        (let
+                          ((fpat (hk-parse-pat)))
+                          (begin
+                            (append! field-pats (list fname fpat))
+                            (when
+                              (hk-match? "comma" nil)
+                              (begin (hk-advance!) (hk-rp-loop))))))))))
+              (hk-rp-loop)
+              (hk-expect! "rbrace" nil)
+              (list :p-rec cname field-pats)))))
      (define
        hk-parse-fexp
        (fn
@@ -696,7 +799,12 @@
                    (:else
                      (do (hk-advance!) (list :p-var (get t "value")))))))
              ((= (get t "type") "conid")
-                (do (hk-advance!) (list :p-con (get t "value") (list))))
+                (do
+                  (hk-advance!)
+                  (cond
+                    ((hk-match? "lbrace" nil)
+                      (hk-parse-rec-pat (get t "value")))
+                    (:else (list :p-con (get t "value") (list))))))
              ((= (get t "type") "qconid")
                (do (hk-advance!) (list :p-con (get t "value") (list))))
              ((= (get t "type") "lparen") (hk-parse-paren-pat))
@@ -762,16 +870,24 @@
            (cond
              ((and (not (nil? t)) (or (= (get t "type") "conid") (= (get t "type") "qconid")))
                (let
-                  ((name (get (hk-advance!) "value")) (args (list)))
-                  (define
-                    hk-pca-loop
-                    (fn
-                      ()
-                      (when
-                        (hk-apat-start? (hk-peek))
-                        (do (append! args (hk-parse-apat)) (hk-pca-loop)))))
-                  (hk-pca-loop)
-                  (list :p-con name args)))
+                  ((name (get (hk-advance!) "value")))
+                  (cond
+                    ((hk-match? "lbrace" nil)
+                      (hk-parse-rec-pat name))
+                    (:else
+                      (let
+                        ((args (list)))
+                        (define
+                          hk-pca-loop
+                          (fn
+                            ()
+                            (when
+                              (hk-apat-start? (hk-peek))
+                              (do
+                                (append! args (hk-parse-apat))
+                                (hk-pca-loop)))))
+                        (hk-pca-loop)
+                        (list :p-con name args))))))
              (:else (hk-parse-apat))))))
      (define
        hk-parse-pat
@@ -1212,16 +1328,47 @@
            (not (hk-match? "conid" nil))
            (hk-err "expected constructor name"))
          (let
-            ((name (get (hk-advance!) "value")) (fields (list)))
-            (define
-              hk-cd-loop
-              (fn
-                ()
-                (when
-                  (hk-atype-start? (hk-peek))
-                  (do (append! fields (hk-parse-atype)) (hk-cd-loop)))))
-            (hk-cd-loop)
-            (list :con-def name fields))))
+            ((name (get (hk-advance!) "value")))
+            (cond
+              ((hk-match? "lbrace" nil)
+                (begin
+                  (hk-advance!)
+                  (let
+                    ((rec-fields (list)))
+                    (define
+                      hk-rec-loop
+                      (fn
+                        ()
+                        (when
+                          (hk-match? "varid" nil)
+                          (let
+                            ((fname (get (hk-advance!) "value")))
+                            (begin
+                              (hk-expect! "reservedop" "::")
+                              (let
+                                ((ftype (hk-parse-type)))
+                                (begin
+                                  (append! rec-fields (list fname ftype))
+                                  (when
+                                    (hk-match? "comma" nil)
+                                    (begin (hk-advance!) (hk-rec-loop))))))))))
+                    (hk-rec-loop)
+                    (hk-expect! "rbrace" nil)
+                    (list :con-rec name rec-fields))))
+              (:else
+                (let
+                  ((fields (list)))
+                  (define
+                    hk-cd-loop
+                    (fn
+                      ()
+                      (when
+                        (hk-atype-start? (hk-peek))
+                        (begin
+                          (append! fields (hk-parse-atype))
+                          (hk-cd-loop)))))
+                  (hk-cd-loop)
+                  (list :con-def name fields)))))))
      (define
        hk-parse-tvars
        (fn
@@ -1586,10 +1733,18 @@
                  (= (hk-peek-type) "eof")
                  (hk-match? "vrbrace" nil)
                  (hk-match? "rbrace" nil))))
+            (define
+              hk-body-step
+              (fn
+                ()
+                (cond
+                  ((hk-match? "reserved" "import")
+                    (append! imports (hk-parse-import)))
+                  (:else (append! decls (hk-parse-decl))))))
            (when
              (not (hk-body-at-end?))
              (do
-                (append! decls (hk-parse-decl))
+                (hk-body-step)
                (define
                  hk-body-loop
                  (fn
@@ -1600,7 +1755,7 @@
                        (hk-advance!)
                        (when
                          (not (hk-body-at-end?))
-                          (append! decls (hk-parse-decl)))
+                          (hk-body-step))
                        (hk-body-loop)))))
                (hk-body-loop)))
            (list imports decls))))
--- a/lib/haskell/runtime.sx
+++ b/lib/haskell/runtime.sx
@@ -12,12 +12,7 @@

 (define
  hk-register-con!
-  (fn
-    (cname arity type-name)
-    (dict-set!
-      hk-constructors
-      cname
-      {:arity arity :type type-name})))
+  (fn (cname arity type-name) (dict-set! hk-constructors cname {:arity arity :type type-name})))

 (define hk-is-con? (fn (name) (has-key? hk-constructors name)))

@@ -48,26 +43,15 @@
  (fn
    (data-node)
    (let
-      ((type-name (nth data-node 1))
-        (cons-list (nth data-node 3)))
+      ((type-name (nth data-node 1)) (cons-list (nth data-node 3)))
      (for-each
-        (fn
-          (cd)
-          (hk-register-con!
-            (nth cd 1)
-            (len (nth cd 2))
-            type-name))
+        (fn (cd) (hk-register-con! (nth cd 1) (len (nth cd 2)) type-name))
        cons-list))))

 ;; (:newtype NAME TVARS CNAME FIELD)
 (define
  hk-register-newtype!
-  (fn
-    (nt-node)
-    (hk-register-con!
-      (nth nt-node 3)
-      1
-      (nth nt-node 1))))
+  (fn (nt-node) (hk-register-con! (nth nt-node 3) 1 (nth nt-node 1))))

 ;; Walk a decls list, registering every `data` / `newtype` decl.
 (define
@@ -78,15 +62,9 @@
      (fn
        (d)
        (cond
-          ((and
-              (list? d)
-              (not (empty? d))
-              (= (first d) "data"))
+          ((and (list? d) (not (empty? d)) (= (first d) "data"))
            (hk-register-data! d))
-          ((and
-              (list? d)
-              (not (empty? d))
-              (= (first d) "newtype"))
+          ((and (list? d) (not (empty? d)) (= (first d) "newtype"))
            (hk-register-newtype! d))
          (:else nil)))
      decls)))
@@ -99,16 +77,12 @@
      ((nil? ast) nil)
      ((not (list? ast)) nil)
      ((empty? ast) nil)
-      ((= (first ast) "program")
-        (hk-register-decls! (nth ast 1)))
-      ((= (first ast) "module")
-        (hk-register-decls! (nth ast 4)))
+      ((= (first ast) "program") (hk-register-decls! (nth ast 1)))
+      ((= (first ast) "module") (hk-register-decls! (nth ast 4)))
      (:else nil))))

 ;; Convenience: source → AST → desugar → register.
-(define
-  hk-load-source!
-  (fn (src) (hk-register-program! (hk-core src))))
+(define hk-load-source! (fn (src) (hk-register-program! (hk-core src))))

 ;; ── Built-in constructors pre-registered ─────────────────────
 ;; Bool — used implicitly by `if`, comparison operators.
@@ -122,9 +96,55 @@
 ;; Standard Prelude types — pre-registered so expression-level
 ;; programs can use them without a `data` decl.
 (hk-register-con! "Nothing" 0 "Maybe")
-(hk-register-con! "Just"    1 "Maybe")
-(hk-register-con! "Left"    1 "Either")
-(hk-register-con! "Right"   1 "Either")
+(hk-register-con! "Just" 1 "Maybe")
+(hk-register-con! "Left" 1 "Either")
+(hk-register-con! "Right" 1 "Either")
 (hk-register-con! "LT" 0 "Ordering")
 (hk-register-con! "EQ" 0 "Ordering")
 (hk-register-con! "GT" 0 "Ordering")
+(hk-register-con! "SomeException" 1 "SomeException")
+
+(define
+  hk-str?
+  (fn (v) (or (string? v) (and (dict? v) (has-key? v "hk-str")))))
+
+(define
+  hk-str-head
+  (fn
+    (v)
+    (if
+      (string? v)
+      (char-code (char-at v 0))
+      (char-code (char-at (get v "hk-str") (get v "hk-off"))))))
+
+(define
+  hk-str-tail
+  (fn
+    (v)
+    (let
+      ((buf (if (string? v) v (get v "hk-str")))
+        (off (if (string? v) 1 (+ (get v "hk-off") 1))))
+      (if (>= off (string-length buf)) (list "[]") {:hk-off off :hk-str buf}))))
+
+(define
+  hk-str-null?
+  (fn
+    (v)
+    (if
+      (string? v)
+      (= (string-length v) 0)
+      (>= (get v "hk-off") (string-length (get v "hk-str"))))))
+
+(define
+  hk-str-to-native
+  (fn
+    (v)
+    (if
+      (string? v)
+      v
+      (let
+        ((buf (get v "hk-str")) (off (get v "hk-off")))
+        (reduce
+          (fn (acc i) (str acc (char-at buf i)))
+          ""
+          (range off (string-length buf)))))))
--- a/lib/haskell/scoreboard.json
+++ b/lib/haskell/scoreboard.json
@@ -1,6 +1,6 @@
 {
-  "date": "2026-05-06",
-  "total_pass": 156,
+  "date": "2026-05-08",
+  "total_pass": 285,
  "total_fail": 0,
  "programs": {
    "fib": {"pass": 2, "fail": 0},
@@ -9,7 +9,7 @@
    "nqueens": {"pass": 2, "fail": 0},
    "calculator": {"pass": 5, "fail": 0},
    "collatz": {"pass": 11, "fail": 0},
-    "palindrome": {"pass": 8, "fail": 0},
+    "palindrome": {"pass": 12, "fail": 0},
    "maybe": {"pass": 12, "fail": 0},
    "fizzbuzz": {"pass": 12, "fail": 0},
    "anagram": {"pass": 9, "fail": 0},
@@ -19,7 +19,25 @@
    "primes": {"pass": 12, "fail": 0},
    "zipwith": {"pass": 9, "fail": 0},
    "matrix": {"pass": 8, "fail": 0},
-    "wordcount": {"pass": 7, "fail": 0},
-    "powers": {"pass": 14, "fail": 0}
+    "wordcount": {"pass": 10, "fail": 0},
+    "powers": {"pass": 14, "fail": 0},
+    "caesar": {"pass": 8, "fail": 0},
+    "runlength-str": {"pass": 9, "fail": 0},
+    "showadt": {"pass": 5, "fail": 0},
+    "showio": {"pass": 5, "fail": 0},
+    "partial": {"pass": 7, "fail": 0},
+    "statistics": {"pass": 5, "fail": 0},
+    "newton": {"pass": 5, "fail": 0},
+    "wordfreq": {"pass": 7, "fail": 0},
+    "mapgraph": {"pass": 6, "fail": 0},
+    "uniquewords": {"pass": 4, "fail": 0},
+    "setops": {"pass": 8, "fail": 0},
+    "shapes": {"pass": 5, "fail": 0},
+    "person": {"pass": 7, "fail": 0},
+    "config": {"pass": 10, "fail": 0},
+    "counter": {"pass": 7, "fail": 0},
+    "accumulate": {"pass": 8, "fail": 0},
+    "safediv": {"pass": 8, "fail": 0},
+    "trycatch": {"pass": 8, "fail": 0}
  }
 }
--- a/lib/haskell/scoreboard.md
+++ b/lib/haskell/scoreboard.md
@@ -1,6 +1,6 @@
 # Haskell-on-SX Scoreboard

-Updated 2026-05-06 · Phase 6 (prelude extras + 18 programs)
+Updated 2026-05-08 · Phase 6 (prelude extras + 18 programs)

 | Program | Tests | Status |
 |---------|-------|--------|
@@ -10,7 +10,7 @@ Updated 2026-05-06 · Phase 6 (prelude extras + 18 programs)
 | nqueens.hs | 2/2 | ✓ |
 | calculator.hs | 5/5 | ✓ |
 | collatz.hs | 11/11 | ✓ |
-| palindrome.hs | 8/8 | ✓ |
+| palindrome.hs | 12/12 | ✓ |
 | maybe.hs | 12/12 | ✓ |
 | fizzbuzz.hs | 12/12 | ✓ |
 | anagram.hs | 9/9 | ✓ |
@@ -20,6 +20,24 @@ Updated 2026-05-06 · Phase 6 (prelude extras + 18 programs)
 | primes.hs | 12/12 | ✓ |
 | zipwith.hs | 9/9 | ✓ |
 | matrix.hs | 8/8 | ✓ |
-| wordcount.hs | 7/7 | ✓ |
+| wordcount.hs | 10/10 | ✓ |
 | powers.hs | 14/14 | ✓ |
-| **Total** | **156/156** | **18/18 programs** |
+| caesar.hs | 8/8 | ✓ |
+| runlength-str.hs | 9/9 | ✓ |
+| showadt.hs | 5/5 | ✓ |
+| showio.hs | 5/5 | ✓ |
+| partial.hs | 7/7 | ✓ |
+| statistics.hs | 5/5 | ✓ |
+| newton.hs | 5/5 | ✓ |
+| wordfreq.hs | 7/7 | ✓ |
+| mapgraph.hs | 6/6 | ✓ |
+| uniquewords.hs | 4/4 | ✓ |
+| setops.hs | 8/8 | ✓ |
+| shapes.hs | 5/5 | ✓ |
+| person.hs | 7/7 | ✓ |
+| config.hs | 10/10 | ✓ |
+| counter.hs | 7/7 | ✓ |
+| accumulate.hs | 8/8 | ✓ |
+| safediv.hs | 8/8 | ✓ |
+| trycatch.hs | 8/8 | ✓ |
+| **Total** | **285/285** | **36/36 programs** |
--- a/lib/haskell/set.sx
+++ b/lib/haskell/set.sx
@@ -0,0 +1,62 @@
+;; set.sx — Phase 12 Data.Set: wraps Data.Map with unit values.
+;;
+;; A Set is a Map from key to (). All set operations delegate to the map
+;; ops, ignoring the value side. Storage representation matches Data.Map:
+;;
+;;   Empty → ("Map-Empty")
+;;   Node  → ("Map-Node" key () left right size)
+;;
+;; Tradeoff: trivial maintenance burden, slight overhead per node from
+;; the unused value slot. Faster path forward than re-implementing the
+;; weight-balanced BST.
+;;
+;; Functions live in this file; the Haskell-level `import Data.Set` /
+;; `import qualified Data.Set as Set` wiring (next Phase 12 box) binds
+;; them under the chosen alias.
+
+(define hk-set-unit (list "Tuple"))
+
+(define hk-set-empty hk-map-empty)
+
+(define hk-set-singleton (fn (k) (hk-map-singleton k hk-set-unit)))
+
+(define hk-set-insert (fn (k s) (hk-map-insert k hk-set-unit s)))
+
+(define hk-set-delete hk-map-delete)
+(define hk-set-member hk-map-member)
+(define hk-set-size hk-map-size)
+(define hk-set-null hk-map-null)
+(define hk-set-to-asc-list hk-map-keys)
+(define hk-set-to-list hk-map-keys)
+
+(define
+  hk-set-from-list
+  (fn (xs) (reduce (fn (acc k) (hk-set-insert k acc)) hk-set-empty xs)))
+
+(define
+  hk-set-union
+  (fn (a b) (hk-map-union-with (fn (x y) hk-set-unit) a b)))
+
+(define
+  hk-set-intersection
+  (fn (a b) (hk-map-intersection-with (fn (x y) hk-set-unit) a b)))
+
+(define hk-set-difference hk-map-difference)
+
+(define
+  hk-set-is-subset-of
+  (fn (a b) (= (hk-map-size (hk-map-difference a b)) 0)))
+
+(define
+  hk-set-filter
+  (fn (p s) (hk-map-filter-with-key (fn (k v) (p k)) s)))
+
+(define hk-set-map (fn (f s) (hk-set-from-list (map f (hk-map-keys s)))))
+
+(define
+  hk-set-foldr
+  (fn (f z s) (hk-map-foldr-with-key (fn (k v acc) (f k acc)) z s)))
+
+(define
+  hk-set-foldl
+  (fn (f z s) (hk-map-foldl-with-key (fn (acc k v) (f acc k)) z s)))
--- a/lib/haskell/test.sh
+++ b/lib/haskell/test.sh
@@ -55,6 +55,8 @@ for FILE in "${FILES[@]}"; do
 (load "lib/haskell/runtime.sx")
 (load "lib/haskell/match.sx")
 (load "lib/haskell/eval.sx")
+(load "lib/haskell/map.sx")
+(load "lib/haskell/set.sx")
 $INFER_LOAD
 (load "lib/haskell/testlib.sx")
 (epoch 2)
@@ -98,6 +100,8 @@ EPOCHS
 (load "lib/haskell/runtime.sx")
 (load "lib/haskell/match.sx")
 (load "lib/haskell/eval.sx")
+(load "lib/haskell/map.sx")
+(load "lib/haskell/set.sx")
 $INFER_LOAD
 (load "lib/haskell/testlib.sx")
 (epoch 2)
--- a/lib/haskell/testlib.sx
+++ b/lib/haskell/testlib.sx
@@ -56,3 +56,21 @@
        (append!
          hk-test-fails
          {:actual actual :expected expected :name name})))))
+
+(define
+  hk-test-error
+  (fn
+    (name thunk expected-substring)
+    (let
+      ((caught (guard (e (true (if (string? e) e (str e)))) (begin (thunk) nil))))
+      (cond
+        ((nil? caught)
+          (do
+            (set! hk-test-fail (+ hk-test-fail 1))
+            (append! hk-test-fails {:actual "no error raised" :expected (str "error containing: " expected-substring) :name name})))
+        ((>= (index-of caught expected-substring) 0)
+          (set! hk-test-pass (+ hk-test-pass 1)))
+        (:else
+          (do
+            (set! hk-test-fail (+ hk-test-fail 1))
+            (append! hk-test-fails {:actual caught :expected (str "error containing: " expected-substring) :name name})))))))
--- a/lib/haskell/tests/class-defaults.sx
+++ b/lib/haskell/tests/class-defaults.sx
@@ -0,0 +1,86 @@
+;; class-defaults.sx — Phase 13: class default method implementations.
+
+;; ── Eq default: myNeq derived from myEq via `not (myEq x y)` ──
+(define
+  hk-myeq-source
+  "class MyEq a where\n  myEq :: a -> a -> Bool\n  myNeq :: a -> a -> Bool\n  myNeq x y = not (myEq x y)\ninstance MyEq Int where\n  myEq x y = x == y\n")
+
+(hk-test
+  "Eq default: myNeq 3 5 = True (no explicit myNeq in instance)"
+  (hk-deep-force (hk-run (str hk-myeq-source "main = myNeq 3 5\n")))
+  (list "True"))
+
+(hk-test
+  "Eq default: myNeq 3 3 = False"
+  (hk-deep-force (hk-run (str hk-myeq-source "main = myNeq 3 3\n")))
+  (list "False"))
+
+(hk-test
+  "Eq default: myEq still works in same instance"
+  (hk-deep-force (hk-run (str hk-myeq-source "main = myEq 7 7\n")))
+  (list "True"))
+
+;; ── Override path: instance can still provide the method explicitly. ──
+(hk-test
+  "Default override: instance-provided beats class default"
+  (hk-deep-force
+    (hk-run
+      "class Hi a where\n  greet :: a -> String\n  greet x = \"default\"\ninstance Hi Bool where\n  greet x = \"override\"\nmain = greet True"))
+  "override")
+
+(hk-test
+  "Default fallback: empty instance picks default"
+  (hk-deep-force
+    (hk-run
+      "class Hi a where\n  greet :: a -> String\n  greet x = \"default\"\ninstance Hi Bool where\nmain = greet True"))
+  "default")
+
+(define
+  hk-myord-source
+  "class MyOrd a where\n  myCmp :: a -> a -> Bool\n  myMax :: a -> a -> a\n  myMin :: a -> a -> a\n  myMax a b = if myCmp a b then a else b\n  myMin a b = if myCmp a b then b else a\ninstance MyOrd Int where\n  myCmp x y = x >= y\n")
+
+(hk-test
+  "Ord default: myMax 3 5 = 5"
+  (hk-deep-force (hk-run (str hk-myord-source "main = myMax 3 5\n")))
+  5)
+
+(hk-test
+  "Ord default: myMax 8 2 = 8"
+  (hk-deep-force (hk-run (str hk-myord-source "main = myMax 8 2\n")))
+  8)
+
+(hk-test
+  "Ord default: myMin 3 5 = 3"
+  (hk-deep-force (hk-run (str hk-myord-source "main = myMin 3 5\n")))
+  3)
+
+(hk-test
+  "Ord default: myMin 8 2 = 2"
+  (hk-deep-force (hk-run (str hk-myord-source "main = myMin 8 2\n")))
+  2)
+
+(hk-test
+  "Ord default: myMax of equals returns first"
+  (hk-deep-force (hk-run (str hk-myord-source "main = myMax 4 4\n")))
+  4)
+
+(define
+  hk-mynum-source
+  "class MyNum a where\n  mySub :: a -> a -> a\n  myLt :: a -> a -> Bool\n  myNegate :: a -> a\n  myAbs :: a -> a\n  myNegate x = mySub (mySub x x) x\n  myAbs x = if myLt x (mySub x x) then myNegate x else x\ninstance MyNum Int where\n  mySub x y = x - y\n  myLt x y = x < y\n")
+
+(hk-test
+  "Num default: myNegate 5 = -5"
+  (hk-deep-force (hk-run (str hk-mynum-source "main = myNegate 5\n")))
+  -5)
+
+(hk-test
+  "Num default: myAbs (myNegate 7) = 7"
+  (hk-deep-force (hk-run (str hk-mynum-source "main = myAbs (myNegate 7)\n")))
+  7)
+
+(hk-test
+  "Num default: myAbs 9 = 9"
+  (hk-deep-force (hk-run (str hk-mynum-source "main = myAbs 9\n")))
+  9)
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/deriving.sx
+++ b/lib/haskell/tests/deriving.sx
@@ -12,14 +12,14 @@
  "deriving Show: constructor with arg"
  (hk-deep-force
    (hk-run "data Wrapper = Wrap Int deriving (Show)\nmain = show (Wrap 42)"))
-  "(Wrap 42)")
+  "Wrap 42")

 (hk-test
  "deriving Show: nested constructors"
  (hk-deep-force
    (hk-run
      "data Tree = Leaf | Node Int Tree Tree deriving (Show)\nmain = show (Node 1 Leaf Leaf)"))
-  "(Node 1 Leaf Leaf)")
+  "Node 1 Leaf Leaf")

 (hk-test
  "deriving Show: second constructor"
@@ -30,6 +30,31 @@

 ;; ─── Eq ──────────────────────────────────────────────────────────────────────

+(hk-test
+  "deriving Show: nested ADT wraps inner constructor in parens"
+  (hk-deep-force
+    (hk-run
+      "data Tree = Leaf | Node Int Tree Tree deriving (Show)\nmain = show (Node 1 Leaf (Node 2 Leaf Leaf))"))
+  "Node 1 Leaf (Node 2 Leaf Leaf)")
+
+(hk-test
+  "deriving Show: Maybe Maybe wraps inner Just"
+  (hk-deep-force (hk-run "main = show (Just (Just 3))"))
+  "Just (Just 3)")
+
+(hk-test
+  "deriving Show: negative argument wrapped in parens"
+  (hk-deep-force (hk-run "main = show (Just (negate 3))"))
+  "Just (-3)")
+
+(hk-test
+  "deriving Show: list element does not need parens"
+  (hk-deep-force
+    (hk-run "data Box = Box [Int] deriving (Show)\nmain = show (Box [1,2,3])"))
+  "Box [1,2,3]")
+
+;; ─── combined Eq + Show ───────────────────────────────────────────────────────
+
 (hk-test
  "deriving Eq: same constructor"
  (hk-deep-force
@@ -58,14 +83,12 @@
      "data Color = Red | Green | Blue deriving (Eq)\nmain = show (Red /= Blue)"))
  "True")

-;; ─── combined Eq + Show ───────────────────────────────────────────────────────
-
 (hk-test
-  "deriving Eq Show: combined in parens"
+  "deriving Eq Show: combined"
  (hk-deep-force
    (hk-run
      "data Shape = Circle Int | Square Int deriving (Eq, Show)\nmain = show (Circle 5)"))
-  "(Circle 5)")
+  "Circle 5")

 (hk-test
  "deriving Eq Show: eq on constructor with arg"
--- a/lib/haskell/tests/errors.sx
+++ b/lib/haskell/tests/errors.sx
@@ -0,0 +1,99 @@
+;; errors.sx — Phase 9 error / undefined / partial-fn coverage via hk-test-error.
+
+;; ── error builtin ────────────────────────────────────────────
+(define
+  hk-as-list
+  (fn
+    (xs)
+    (cond
+      ((and (list? xs) (= (first xs) "[]")) (list))
+      ((and (list? xs) (= (first xs) ":"))
+        (cons (nth xs 1) (hk-as-list (nth xs 2))))
+      (:else xs))))
+
+(hk-test-error
+  "error: raises with literal message"
+  (fn () (hk-deep-force (hk-run "main = error \"boom\"")))
+  "hk-error: boom")
+
+(hk-test-error
+  "error: raises with computed message"
+  (fn () (hk-deep-force (hk-run "main = error (\"oops: \" ++ show 42)")))
+  "hk-error: oops: 42")
+
+;; ── undefined ────────────────────────────────────────────────
+(hk-test-error
+  "error: nested in if branch (only fires when forced)"
+  (fn
+    ()
+    (hk-deep-force (hk-run "main = if 1 == 1 then error \"taken\" else 0")))
+  "taken")
+
+(hk-test-error
+  "undefined: raises Prelude.undefined"
+  (fn () (hk-deep-force (hk-run "main = undefined")))
+  "Prelude.undefined")
+
+;; The non-strict path: undefined doesn't fire when not forced.
+(hk-test-error
+  "undefined: forced via arithmetic"
+  (fn () (hk-deep-force (hk-run "main = undefined + 1")))
+  "Prelude.undefined")
+
+;; ── partial functions ───────────────────────────────────────
+(hk-test
+  "undefined: lazy, not forced when discarded"
+  (hk-deep-force (hk-run "main = let _ = undefined in 5"))
+  5)
+
+(hk-test-error
+  "head []: raises Prelude.head: empty list"
+  (fn () (hk-deep-force (hk-run "main = head []")))
+  "Prelude.head: empty list")
+
+(hk-test-error
+  "tail []: raises Prelude.tail: empty list"
+  (fn () (hk-deep-force (hk-run "main = tail []")))
+  "Prelude.tail: empty list")
+
+;; head and tail still work on non-empty lists.
+(hk-test-error
+  "fromJust Nothing: raises Maybe.fromJust: Nothing"
+  (fn () (hk-deep-force (hk-run "main = fromJust Nothing")))
+  "Maybe.fromJust: Nothing")
+
+(hk-test
+  "head [42]: still works"
+  (hk-deep-force (hk-run "main = head [42]"))
+  42)
+
+;; ── error in IO context ─────────────────────────────────────
+(hk-test
+  "tail [1,2,3]: still works"
+  (hk-as-list (hk-deep-force (hk-run "main = tail [1,2,3]")))
+  (list 2 3))
+
+(hk-test
+  "hk-run-io: error in main lands in io-lines"
+  (let
+    ((lines (hk-run-io "main = error \"caught here\"")))
+    (>= (index-of (str lines) "caught here") 0))
+  true)
+
+;; ── hk-test-error helper itself ─────────────────────────────
+(hk-test
+  "hk-run-io: putStrLn before error preserves earlier output"
+  (let
+    ((lines (hk-run-io "main = do { putStrLn \"first\"; error \"died\"; putStrLn \"never\" }")))
+    (and
+      (>= (index-of (str lines) "first") 0)
+      (>= (index-of (str lines) "died") 0)))
+  true)
+
+;; hk-as-list helper for converting a forced Haskell cons into an SX list.
+(hk-test-error
+  "hk-test-error: matches partial substring inside wrapped exception"
+  (fn () (hk-deep-force (hk-run "main = error \"unique-marker-xyz\"")))
+  "unique-marker-xyz")
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/eval.sx
+++ b/lib/haskell/tests/eval.sx
@@ -231,16 +231,82 @@
  1)

 ;; ── Laziness: app args evaluate only when forced ──
+(hk-test
+  "error builtin: raises with hk-error prefix"
+  (guard
+    (e (true (>= (index-of e "hk-error: boom") 0)))
+    (begin (hk-deep-force (hk-run "main = error \"boom\"")) false))
+  true)
+
+(hk-test
+  "error builtin: raises with computed message"
+  (guard
+    (e (true (>= (index-of e "hk-error: oops: 42") 0)))
+    (begin
+      (hk-deep-force (hk-run "main = error (\"oops: \" ++ show 42)"))
+      false))
+  true)
+
+(hk-test
+  "undefined: raises hk-error with Prelude.undefined message"
+  (guard
+    (e (true (>= (index-of e "hk-error: Prelude.undefined") 0)))
+    (begin (hk-deep-force (hk-run "main = undefined")) false))
+  true)
+
+(hk-test
+  "undefined: lazy — only fires when forced"
+  (hk-deep-force (hk-run "main = if True then 42 else undefined"))
+  42)
+
+(hk-test
+  "head []: raises Prelude.head: empty list"
+  (guard
+    (e (true (>= (index-of e "Prelude.head: empty list") 0)))
+    (begin (hk-deep-force (hk-run "main = head []")) false))
+  true)
+
+(hk-test
+  "tail []: raises Prelude.tail: empty list"
+  (guard
+    (e (true (>= (index-of e "Prelude.tail: empty list") 0)))
+    (begin (hk-deep-force (hk-run "main = tail []")) false))
+  true)
+
+;; ── not / id built-ins ──
+(hk-test
+  "fromJust Nothing: raises Maybe.fromJust: Nothing"
+  (guard
+    (e (true (>= (index-of e "Maybe.fromJust: Nothing") 0)))
+    (begin (hk-deep-force (hk-run "main = fromJust Nothing")) false))
+  true)
+(hk-test
+  "fromJust (Just 5) = 5"
+  (hk-deep-force (hk-run "main = fromJust (Just 5)"))
+  5)
+(hk-test
+  "head [42] = 42 (still works for non-empty)"
+  (hk-deep-force (hk-run "main = head [42]"))
+  42)
+
+(hk-test-error
+  "hk-test-error helper: catches matching error"
+  (fn () (hk-deep-force (hk-run "main = error \"boom\"")))
+  "hk-error: boom")
+
+(hk-test-error
+  "hk-test-error helper: catches head [] error"
+  (fn () (hk-deep-force (hk-run "main = head []")))
+  "Prelude.head: empty list")
+
 (hk-test
  "second arg never forced"
-  (hk-eval-expr-source
-    "(\\x y -> x) 1 (error \"never\")")
+  (hk-eval-expr-source "(\\x y -> x) 1 (error \"never\")")
  1)

 (hk-test
  "first arg never forced"
-  (hk-eval-expr-source
-    "(\\x y -> y) (error \"never\") 99")
+  (hk-eval-expr-source "(\\x y -> y) (error \"never\") 99")
  99)

 (hk-test
@@ -251,9 +317,7 @@

 (hk-test
  "lazy: const drops its second argument"
-  (hk-prog-val
-    "const x y = x\nresult = const 5 (error \"boom\")"
-    "result")
+  (hk-prog-val "const x y = x\nresult = const 5 (error \"boom\")" "result")
  5)

 (hk-test
@@ -270,9 +334,10 @@
    "result")
  (list "True"))

-;; ── not / id built-ins ──
 (hk-test "not True" (hk-eval-expr-source "not True") (list "False"))
+
 (hk-test "not False" (hk-eval-expr-source "not False") (list "True"))
+
 (hk-test "id" (hk-eval-expr-source "id 42") 42)

 {:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/exceptions.sx
+++ b/lib/haskell/tests/exceptions.sx
@@ -0,0 +1,105 @@
+;; Phase 16 — Exception handling unit tests.
+
+(hk-test
+  "catch — success path returns the action result"
+  (hk-deep-force
+    (hk-run
+      "main = catch (return 42) (\\(SomeException m) -> return 0)"))
+  (list "IO" 42))
+
+(hk-test
+  "catch — error caught, handler receives message"
+  (hk-deep-force
+    (hk-run
+      "main = catch (error \"boom\") (\\(SomeException m) -> return m)"))
+  (list "IO" "boom"))
+
+(hk-test
+  "try — success returns Right v"
+  (hk-deep-force
+    (hk-run "main = try (return 42)"))
+  (list "IO" (list "Right" 42)))
+
+(hk-test
+  "try — error returns Left (SomeException msg)"
+  (hk-deep-force
+    (hk-run "main = try (error \"oops\")"))
+  (list "IO" (list "Left" (list "SomeException" "oops"))))
+
+(hk-test
+  "handle — flip catch — caught error message"
+  (hk-deep-force
+    (hk-run
+      "main = handle (\\(SomeException m) -> return m) (error \"hot\")"))
+  (list "IO" "hot"))
+
+(hk-test
+  "throwIO + catch — handler sees the SomeException"
+  (hk-deep-force
+    (hk-run
+      "main = catch (throwIO (SomeException \"bang\")) (\\(SomeException m) -> return m)"))
+  (list "IO" "bang"))
+
+(hk-test
+  "throwIO + try — Left side"
+  (hk-deep-force
+    (hk-run
+      "main = try (throwIO (SomeException \"x\"))"))
+  (list "IO" (list "Left" (list "SomeException" "x"))))
+
+(hk-test
+  "evaluate — pure value returns IO v"
+  (hk-deep-force
+    (hk-run "main = evaluate (1 + 2 + 3)"))
+  (list "IO" 6))
+
+(hk-test
+  "evaluate — error surfaces as catchable exception"
+  (hk-deep-force
+    (hk-run
+      "main = catch (evaluate (error \"deep\")) (\\(SomeException m) -> return m)"))
+  (list "IO" "deep"))
+
+(hk-test
+  "nested catch — inner handler runs first"
+  (hk-deep-force
+    (hk-run
+      "main = catch (catch (error \"inner\") (\\(SomeException m) -> error (m ++ \"-rethrown\"))) (\\(SomeException m) -> return m)"))
+  (list "IO" "inner-rethrown"))
+
+(hk-test
+  "catch chain — handler can succeed inside IO"
+  (hk-deep-force
+    (hk-run
+      "main = do { x <- catch (error \"e1\") (\\(SomeException m) -> return 100); return (x + 1) }"))
+  (list "IO" 101))
+
+(hk-test
+  "try then bind on Right"
+  (hk-deep-force
+    (hk-run
+      "branch (Right v) = return (v * 2)
+branch (Left _) = return 0
+main = do { r <- try (return 21); branch r }"))
+  (list "IO" 42))
+
+(hk-test
+  "try then bind on Left"
+  (hk-deep-force
+    (hk-run
+      "branch (Right _) = return \"ok\"
+branch (Left (SomeException m)) = return m
+main = do { r <- try (error \"failed\"); branch r }"))
+  (list "IO" "failed"))
+
+(hk-test
+  "catch — handler can use closed-over IORef"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef
+main = do
+  r <- IORef.newIORef 0
+  catch (error \"x\") (\\(SomeException m) -> IORef.writeIORef r 7)
+  v <- IORef.readIORef r
+  return v"))
+  (list "IO" 7))
--- a/lib/haskell/tests/instance-where.sx
+++ b/lib/haskell/tests/instance-where.sx
@@ -0,0 +1,31 @@
+;; instance-where.sx — Phase 13: where-clauses inside instance bodies.
+
+(hk-test
+  "instance method body with where-helper (Bool)"
+  (hk-deep-force
+    (hk-run
+      "class Greet a where\n  greet :: a -> String\ninstance Greet Bool where\n  greet x = mkMsg x\n    where mkMsg True = \"yes\"\n          mkMsg False = \"no\"\nmain = greet True"))
+  "yes")
+
+(hk-test
+  "instance method body with where-helper (False branch)"
+  (hk-deep-force
+    (hk-run
+      "class Greet a where\n  greet :: a -> String\ninstance Greet Bool where\n  greet x = mkMsg x\n    where mkMsg True = \"yes\"\n          mkMsg False = \"no\"\nmain = greet False"))
+  "no")
+
+(hk-test
+  "instance method body with where-binding referenced multiple times"
+  (hk-deep-force
+    (hk-run
+      "class Twice a where\n  twice :: a -> Int\ninstance Twice Int where\n  twice x = h + h\n    where h = x + 1\nmain = twice 5"))
+  12)
+
+(hk-test
+  "instance method body with multi-binding where"
+  (hk-deep-force
+    (hk-run
+      "class Calc a where\n  calc :: a -> Int\ninstance Calc Int where\n  calc x = a + b\n    where a = x * 2\n          b = x + 1\nmain = calc 3"))
+  10)
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/io-input.sx
+++ b/lib/haskell/tests/io-input.sx
@@ -64,12 +64,11 @@

 (hk-test
  "readFile error on missing file"
-  (guard
-    (e (true (>= (index-of e "file not found") 0)))
-    (begin
-      (set! hk-vfs (dict))
-      (hk-run-io "main = readFile \"no.txt\" >>= putStrLn")
-      false))
+  (begin
+    (set! hk-vfs (dict))
+    (let
+      ((lines (hk-run-io "main = readFile \"no.txt\" >>= putStrLn")))
+      (>= (index-of (str lines) "file not found") 0)))
  true)

 (hk-test
--- a/lib/haskell/tests/ioref.sx
+++ b/lib/haskell/tests/ioref.sx
@@ -0,0 +1,94 @@
+;; Phase 15 — IORef unit tests.
+
+(hk-test
+  "newIORef + readIORef returns initial value"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\nmain = do { r <- IORef.newIORef 42; v <- IORef.readIORef r; return v }"))
+  (list "IO" 42))
+
+(hk-test
+  "writeIORef updates the cell"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\nmain = do { r <- IORef.newIORef 0; IORef.writeIORef r 99; v <- IORef.readIORef r; return v }"))
+  (list "IO" 99))
+
+(hk-test
+  "writeIORef returns IO ()"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\nmain = do { r <- IORef.newIORef 0; IORef.writeIORef r 1 }"))
+  (list "IO" (list "Tuple")))
+
+(hk-test
+  "modifyIORef applies a function"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\nmain = do { r <- IORef.newIORef 5; IORef.modifyIORef r (\\x -> x * 2); v <- IORef.readIORef r; return v }"))
+  (list "IO" 10))
+
+(hk-test
+  "modifyIORef' (strict) applies a function"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\nmain = do { r <- IORef.newIORef 7; IORef.modifyIORef' r (\\x -> x + 3); v <- IORef.readIORef r; return v }"))
+  (list "IO" 10))
+
+(hk-test
+  "two reads return the same value"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\nmain = do { r <- IORef.newIORef 11; a <- IORef.readIORef r; b <- IORef.readIORef r; return (a + b) }"))
+  (list "IO" 22))
+
+(hk-test
+  "shared ref across do-steps: write then read"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\nmain = do { r <- IORef.newIORef 1; IORef.writeIORef r 2; IORef.writeIORef r 3; v <- IORef.readIORef r; return v }"))
+  (list "IO" 3))
+
+(hk-test
+  "two refs are independent"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\nmain = do { r1 <- IORef.newIORef 1; r2 <- IORef.newIORef 2; IORef.writeIORef r1 10; a <- IORef.readIORef r1; b <- IORef.readIORef r2; return (a + b) }"))
+  (list "IO" 12))
+
+(hk-test
+  "string-valued IORef"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\nmain = do { r <- IORef.newIORef \"hi\"; IORef.writeIORef r \"bye\"; v <- IORef.readIORef r; return v }"))
+  (list "IO" "bye"))
+
+(hk-test
+  "list-valued IORef + cons"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\nmain = do { r <- IORef.newIORef [1,2,3]; IORef.modifyIORef r (\\xs -> 0 : xs); v <- IORef.readIORef r; return v }"))
+  (list
+    "IO"
+    (list ":" 0 (list ":" 1 (list ":" 2 (list ":" 3 (list "[]")))))))
+
+(hk-test
+  "counter loop: increment N times"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\nloop r 0 = return ()\nloop r n = do { IORef.modifyIORef r (\\x -> x + 1); loop r (n - 1) }\nmain = do { r <- IORef.newIORef 0; loop r 10; v <- IORef.readIORef r; return v }"))
+  (list "IO" 10))
+
+(hk-test
+  "modifyIORef' inside a loop"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\ngo r 0 = return ()\ngo r n = do { IORef.modifyIORef' r (\\x -> x + n); go r (n - 1) }\nmain = do { r <- IORef.newIORef 0; go r 5; v <- IORef.readIORef r; return v }"))
+  (list "IO" 15))
+
+(hk-test
+  "newIORef inside a function passed via parameter"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.IORef as IORef\nbump r = IORef.modifyIORef r (\\x -> x + 100)\nmain = do { r <- IORef.newIORef 1; bump r; v <- IORef.readIORef r; return v }"))
+  (list "IO" 101))
--- a/lib/haskell/tests/map.sx
+++ b/lib/haskell/tests/map.sx
@@ -0,0 +1,196 @@
+;; map.sx — Phase 11 Data.Map unit tests.
+;;
+;; Tests both the SX-level `hk-map-*` helpers and the Haskell-level
+;; `Map.*` aliases bound by the import handler.
+
+(define
+  hk-as-list
+  (fn
+    (xs)
+    (cond
+      ((and (list? xs) (= (first xs) "[]")) (list))
+      ((and (list? xs) (= (first xs) ":"))
+        (cons (nth xs 1) (hk-as-list (nth xs 2))))
+      (:else xs))))
+
+;; ── SX-level (direct hk-map-*) ───────────────────────────────
+(hk-test
+  "hk-map-empty: size 0, null true"
+  (list (hk-map-size hk-map-empty) (hk-map-null hk-map-empty))
+  (list 0 true))
+
+(hk-test
+  "hk-map-singleton: lookup hit"
+  (let
+    ((m (hk-map-singleton 5 "five")))
+    (list (hk-map-size m) (hk-map-lookup 5 m)))
+  (list 1 (list "Just" "five")))
+
+(hk-test
+  "hk-map-insert: lookup hit on inserted"
+  (let ((m (hk-map-insert 1 "a" hk-map-empty))) (hk-map-lookup 1 m))
+  (list "Just" "a"))
+
+(hk-test
+  "hk-map-lookup: miss returns Nothing"
+  (hk-map-lookup 99 (hk-map-singleton 1 "a"))
+  (list "Nothing"))
+
+(hk-test
+  "hk-map-insert: overwrites existing key"
+  (let
+    ((m (hk-map-insert 1 "second" (hk-map-insert 1 "first" hk-map-empty))))
+    (hk-map-lookup 1 m))
+  (list "Just" "second"))
+
+(hk-test
+  "hk-map-delete: removes key"
+  (let
+    ((m (hk-map-insert 2 "b" (hk-map-insert 1 "a" hk-map-empty))))
+    (let
+      ((m2 (hk-map-delete 1 m)))
+      (list (hk-map-size m2) (hk-map-lookup 1 m2) (hk-map-lookup 2 m2))))
+  (list 1 (list "Nothing") (list "Just" "b")))
+
+(hk-test
+  "hk-map-delete: missing key is no-op"
+  (let ((m (hk-map-singleton 1 "a"))) (hk-map-size (hk-map-delete 99 m)))
+  1)
+
+(hk-test
+  "hk-map-member: true on existing"
+  (hk-map-member 1 (hk-map-singleton 1 "a"))
+  true)
+
+(hk-test
+  "hk-map-member: false on missing"
+  (hk-map-member 99 (hk-map-singleton 1 "a"))
+  false)
+
+(hk-test
+  "hk-map-from-list: builds map; keys sorted"
+  (hk-map-keys
+    (hk-map-from-list
+      (list (list 3 "c") (list 1 "a") (list 5 "e") (list 2 "b"))))
+  (list 1 2 3 5))
+
+(hk-test
+  "hk-map-from-list: duplicates — last wins"
+  (hk-map-lookup
+    1
+    (hk-map-from-list (list (list 1 "first") (list 1 "second"))))
+  (list "Just" "second"))
+
+(hk-test
+  "hk-map-to-asc-list: ordered traversal"
+  (hk-map-to-asc-list
+    (hk-map-from-list (list (list 3 "c") (list 1 "a") (list 2 "b"))))
+  (list (list 1 "a") (list 2 "b") (list 3 "c")))
+
+(hk-test
+  "hk-map-elems: in key order"
+  (hk-map-elems
+    (hk-map-from-list (list (list 3 30) (list 1 10) (list 2 20))))
+  (list 10 20 30))
+
+(hk-test
+  "hk-map-union-with: combines duplicates"
+  (hk-map-to-asc-list
+    (hk-map-union-with
+      (fn (a b) (str a "+" b))
+      (hk-map-from-list (list (list 1 "a") (list 2 "b")))
+      (hk-map-from-list (list (list 2 "B") (list 3 "c")))))
+  (list (list 1 "a") (list 2 "b+B") (list 3 "c")))
+
+(hk-test
+  "hk-map-intersection-with: keeps shared keys"
+  (hk-map-to-asc-list
+    (hk-map-intersection-with
+      +
+      (hk-map-from-list (list (list 1 10) (list 2 20)))
+      (hk-map-from-list (list (list 2 200) (list 3 30)))))
+  (list (list 2 220)))
+
+(hk-test
+  "hk-map-difference: drops m2 keys"
+  (hk-map-keys
+    (hk-map-difference
+      (hk-map-from-list (list (list 1 "a") (list 2 "b") (list 3 "c")))
+      (hk-map-from-list (list (list 2 "x")))))
+  (list 1 3))
+
+(hk-test
+  "hk-map-foldl-with-key: in-order accumulate"
+  (hk-map-foldl-with-key
+    (fn (acc k v) (str acc k v))
+    ""
+    (hk-map-from-list (list (list 3 "c") (list 1 "a") (list 2 "b"))))
+  "1a2b3c")
+
+(hk-test
+  "hk-map-map-with-key: transforms values"
+  (hk-map-to-asc-list
+    (hk-map-map-with-key
+      (fn (k v) (* k v))
+      (hk-map-from-list (list (list 2 10) (list 3 100)))))
+  (list (list 2 20) (list 3 300)))
+
+(hk-test
+  "hk-map-filter-with-key: keeps matches"
+  (hk-map-keys
+    (hk-map-filter-with-key
+      (fn (k v) (> k 1))
+      (hk-map-from-list (list (list 1 "a") (list 2 "b") (list 3 "c")))))
+  (list 2 3))
+
+(hk-test
+  "hk-map-adjust: applies f to existing"
+  (hk-map-lookup
+    1
+    (hk-map-adjust (fn (v) (* v 10)) 1 (hk-map-singleton 1 5)))
+  (list "Just" 50))
+
+(hk-test
+  "hk-map-insert-with: combines on existing"
+  (hk-map-lookup 1 (hk-map-insert-with + 1 5 (hk-map-singleton 1 10)))
+  (list "Just" 15))
+
+(hk-test
+  "hk-map-alter: Nothing → delete"
+  (hk-map-size
+    (hk-map-alter
+      (fn (mv) (list "Nothing"))
+      1
+      (hk-map-from-list (list (list 1 "a") (list 2 "b")))))
+  1)
+
+;; ── Haskell-level (Map.*) via import wiring ─────────────────
+(hk-test
+  "Map.size after Map.insert chain"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.Map as Map\nmain = Map.size (Map.insert 2 \"b\" (Map.insert 1 \"a\" Map.empty))"))
+  2)
+
+(hk-test
+  "Map.lookup hit"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.Map as Map\nmain = Map.lookup 1 (Map.insert 1 \"a\" Map.empty)"))
+  (list "Just" "a"))
+
+(hk-test
+  "Map.lookup miss"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.Map as Map\nmain = Map.lookup 99 (Map.insert 1 \"a\" Map.empty)"))
+  (list "Nothing"))
+
+(hk-test
+  "Map.member true"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.Map as Map\nmain = Map.member 5 (Map.insert 5 \"x\" Map.empty)"))
+  (list "True"))
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/numerics.sx
+++ b/lib/haskell/tests/numerics.sx
@@ -0,0 +1,180 @@
+;; numerics.sx — Phase 10 numeric tower verification.
+;;
+;; Practical integer-precision limit in Haskell-on-SX:
+;;   • Raw SX `(* a b)` stays exact up to ±2^62 (≈ 4.6e18, OCaml int63).
+;;   • BUT the Haskell tokenizer/parser parses an integer literal as a float
+;;     once it exceeds 2^53 (≈ 9.007e15). Once any operand is a float, the
+;;     binop result is a float (and decimal-precision is lost past 2^53).
+;;   • Therefore: programs that stay below ~9e15 are exact; larger literals
+;;     or accumulated products silently become floats. `factorial 18` is the
+;;     last factorial that stays exact (6.4e15); `factorial 19` already floats.
+;;
+;; In Haskell terms, `Int` and `Integer` both currently map to SX number, so
+;; we don't yet support arbitrary-precision Integer. Documented; unbounded
+;; Integer is out of scope for Phase 10 — see Phase 11+ if it becomes needed.
+
+(define
+  hk-as-list
+  (fn
+    (xs)
+    (cond
+      ((and (list? xs) (= (first xs) "[]")) (list))
+      ((and (list? xs) (= (first xs) ":"))
+        (cons (nth xs 1) (hk-as-list (nth xs 2))))
+      (:else xs))))
+
+(hk-test
+  "factorial 10 = 3628800 (small, exact)"
+  (hk-deep-force
+    (hk-run "fact 0 = 1\nfact n = n * fact (n - 1)\nmain = fact 10"))
+  3628800)
+
+(hk-test
+  "factorial 15 = 1307674368000 (mid-range, exact)"
+  (hk-deep-force
+    (hk-run "fact 0 = 1\nfact n = n * fact (n - 1)\nmain = fact 15"))
+  1307674368000)
+
+(hk-test
+  "factorial 18 = 6402373705728000 (last exact factorial)"
+  (hk-deep-force
+    (hk-run "fact 0 = 1\nfact n = n * fact (n - 1)\nmain = fact 18"))
+  6402373705728000)
+
+(hk-test
+  "1000000 * 1000000 = 10^12 (exact)"
+  (hk-deep-force (hk-run "main = 1000000 * 1000000"))
+  1000000000000)
+
+(hk-test
+  "1000000000 * 1000000000 = 10^18 (exact, at boundary)"
+  (hk-deep-force (hk-run "main = 1000000000 * 1000000000"))
+  1e+18)
+
+(hk-test
+  "2^62 boundary: pow accumulates exactly"
+  (hk-deep-force
+    (hk-run "pow b 0 = 1\npow b n = b * pow b (n - 1)\nmain = pow 2 62"))
+  4.6116860184273879e+18)
+
+(hk-test
+  "show factorial 12 = 479001600 (whole, fits in 32-bit)"
+  (hk-deep-force
+    (hk-run "fact 0 = 1\nfact n = n * fact (n - 1)\nmain = show (fact 12)"))
+  "479001600")
+
+(hk-test
+  "negate large positive — preserves magnitude"
+  (hk-deep-force (hk-run "main = negate 1000000000000000000"))
+  -1e+18)
+
+(hk-test
+  "abs negative large — preserves magnitude"
+  (hk-deep-force (hk-run "main = abs (negate 1000000000000000000)"))
+  1e+18)
+
+(hk-test
+  "div on large ints"
+  (hk-deep-force (hk-run "main = div 1000000000000000000 1000000000"))
+  1000000000)
+
+(hk-test
+  "fromIntegral 42 = 42 (identity in our runtime)"
+  (hk-deep-force (hk-run "main = fromIntegral 42"))
+  42)
+
+(hk-test
+  "fromIntegral preserves negative"
+  (hk-deep-force (hk-run "main = fromIntegral (negate 7)"))
+  -7)
+
+(hk-test
+  "fromIntegral round-trips through arithmetic"
+  (hk-deep-force (hk-run "main = fromIntegral 5 + fromIntegral 3"))
+  8)
+
+(hk-test
+  "fromIntegral in a program (mixing with map)"
+  (hk-as-list (hk-deep-force (hk-run "main = map fromIntegral [1,2,3]")))
+  (list 1 2 3))
+
+(hk-test
+  "toInteger 100 = 100 (identity)"
+  (hk-deep-force (hk-run "main = toInteger 100"))
+  100)
+
+(hk-test
+  "fromInteger 7 = 7 (identity)"
+  (hk-deep-force (hk-run "main = fromInteger 7"))
+  7)
+
+(hk-test
+  "toInteger / fromInteger round-trip"
+  (hk-deep-force (hk-run "main = fromInteger (toInteger 42)"))
+  42)
+
+(hk-test
+  "toInteger preserves negative"
+  (hk-deep-force (hk-run "main = toInteger (negate 13)"))
+  -13)
+
+(hk-test
+  "show 3.14 = 3.14"
+  (hk-deep-force (hk-run "main = show 3.14"))
+  "3.14")
+
+(hk-test
+  "show 1.0e10 — whole-valued float renders as decimal (int/float ambiguity)"
+  (hk-deep-force (hk-run "main = show 1.0e10"))
+  "10000000000")
+
+(hk-test
+  "show 0.001 uses scientific form (sub-0.1)"
+  (hk-deep-force (hk-run "main = show 0.001"))
+  "1.0e-3")
+
+(hk-test
+  "show negative float"
+  (hk-deep-force (hk-run "main = show (negate 3.14)"))
+  "-3.14")
+
+(hk-test "sqrt 16 = 4" (hk-deep-force (hk-run "main = sqrt 16")) 4)
+
+(hk-test "floor 3.7 = 3" (hk-deep-force (hk-run "main = floor 3.7")) 3)
+
+(hk-test "ceiling 3.2 = 4" (hk-deep-force (hk-run "main = ceiling 3.2")) 4)
+
+(hk-test
+  "ceiling on whole = self"
+  (hk-deep-force (hk-run "main = ceiling 4"))
+  4)
+
+(hk-test "round 2.6 = 3" (hk-deep-force (hk-run "main = round 2.6")) 3)
+
+(hk-test
+  "truncate -3.7 = -3"
+  (hk-deep-force (hk-run "main = truncate (negate 3.7)"))
+  -3)
+
+(hk-test "recip 4.0 = 0.25" (hk-deep-force (hk-run "main = recip 4.0")) 0.25)
+
+(hk-test "1.0 / 4.0 = 0.25" (hk-deep-force (hk-run "main = 1.0 / 4.0")) 0.25)
+
+(hk-test
+  "fromRational 0.5 = 0.5 (identity)"
+  (hk-deep-force (hk-run "main = fromRational 0.5"))
+  0.5)
+
+(hk-test "pi ≈ 3.14159" (hk-deep-force (hk-run "main = pi")) 3.14159)
+
+(hk-test "exp 0 = 1" (hk-deep-force (hk-run "main = exp 0")) 1)
+
+(hk-test "sin 0 = 0" (hk-deep-force (hk-run "main = sin 0")) 0)
+
+(hk-test "cos 0 = 1" (hk-deep-force (hk-run "main = cos 0")) 1)
+
+(hk-test "2 ** 10 = 1024" (hk-deep-force (hk-run "main = 2 ** 10")) 1024)
+
+(hk-test "log (exp 5) ≈ 5" (hk-deep-force (hk-run "main = log (exp 5)")) 5)
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/parse-extras.sx
+++ b/lib/haskell/tests/parse-extras.sx
@@ -0,0 +1,102 @@
+;; Phase 17 — parser polish unit tests.
+
+(hk-test
+  "type-ann: literal int annotated"
+  (hk-deep-force (hk-run "main = (42 :: Int)"))
+  42)
+
+(hk-test
+  "type-ann: arithmetic annotated"
+  (hk-deep-force (hk-run "main = (1 + 2 :: Int)"))
+  3)
+
+(hk-test
+  "type-ann: function arg annotated"
+  (hk-deep-force
+    (hk-run "f x = x + 1\nmain = f (1 :: Int)"))
+  2)
+
+(hk-test
+  "type-ann: string annotated"
+  (hk-deep-force (hk-run "main = (\"hi\" :: String)"))
+  "hi")
+
+(hk-test
+  "type-ann: bool annotated"
+  (hk-deep-force (hk-run "main = (True :: Bool)"))
+  (list "True"))
+
+(hk-test
+  "type-ann: tuple annotated"
+  (hk-deep-force (hk-run "main = ((1, 2) :: (Int, Int))"))
+  (list "Tuple" 1 2))
+
+(hk-test
+  "type-ann: nested annotation in arithmetic"
+  (hk-deep-force (hk-run "main = (1 :: Int) + (2 :: Int)"))
+  3)
+
+(hk-test
+  "type-ann: function-typed annotation passes through eval"
+  (hk-deep-force
+    (hk-run "main = let f = ((\\x -> x + 1) :: Int -> Int) in f 5"))
+  6)
+
+(hk-test
+  "no regression: plain parens still work"
+  (hk-deep-force (hk-run "main = (5)"))
+  5)
+
+(hk-test
+  "no regression: 3-tuple still works"
+  (hk-deep-force (hk-run "main = (1, 2, 3)"))
+  (list "Tuple" 1 2 3))
+
+(hk-test
+  "no regression: section-left still works"
+  (hk-deep-force (hk-run "main = (3 +) 4"))
+  7)
+
+(hk-test
+  "no regression: section-right still works"
+  (hk-deep-force (hk-run "main = (+ 3) 4"))
+  7)
+
+(hk-test
+  "import: still works as the very first decl"
+  (hk-deep-force
+    (hk-run "import qualified Data.IORef as I
+main = do { r <- I.newIORef 7; I.readIORef r }"))
+  (list "IO" 7))
+
+(hk-test
+  "import: between decls — after main"
+  (hk-deep-force
+    (hk-run "main = do { r <- I.newIORef 11; I.readIORef r }
+import qualified Data.IORef as I"))
+  (list "IO" 11))
+
+(hk-test
+  "import: between two decls — uses helper after import"
+  (hk-deep-force
+    (hk-run "f x = x + 100
+import qualified Data.IORef as I
+main = do { r <- I.newIORef 5; I.modifyIORef r f; I.readIORef r }"))
+  (list "IO" 105))
+
+(hk-test
+  "import: two imports in different positions"
+  (hk-deep-force
+    (hk-run "import qualified Data.IORef as I
+helper x = x * 2
+import qualified Data.Map as M
+main = do { r <- I.newIORef (helper 21); I.readIORef r }"))
+  (list "IO" 42))
+
+(hk-test
+  "import: unqualified, mid-file"
+  (hk-deep-force
+    (hk-run "go x = x
+import Data.IORef
+main = go 9"))
+  9)
--- a/lib/haskell/tests/program-accumulate.sx
+++ b/lib/haskell/tests/program-accumulate.sx
@@ -0,0 +1,81 @@
+;; accumulate.hs — accumulate results into an IORef [Int] (Phase 15 conformance).
+
+(define
+  hk-accumulate-source
+  "import qualified Data.IORef as IORef\n\npush :: IORef [Int] -> Int -> IO ()\npush r x = IORef.modifyIORef r (\\xs -> x : xs)\n\npushAll :: IORef [Int] -> [Int] -> IO ()\npushAll r [] = return ()\npushAll r (x:xs) = do\n  push r x\n  pushAll r xs\n\nreadReversed :: IORef [Int] -> IO [Int]\nreadReversed r = do\n  xs <- IORef.readIORef r\n  return (reverse xs)\n\ndoubleEach :: IORef [Int] -> [Int] -> IO ()\ndoubleEach r [] = return ()\ndoubleEach r (x:xs) = do\n  push r (x * 2)\n  doubleEach r xs\n\nsumIntoRef :: IORef Int -> [Int] -> IO ()\nsumIntoRef r [] = return ()\nsumIntoRef r (x:xs) = do\n  IORef.modifyIORef r (\\acc -> acc + x)\n  sumIntoRef r xs\n\n")
+
+(hk-test
+  "accumulate.hs — push three then read length"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-accumulate-source
+        "main = do { r <- IORef.newIORef []; push r 1; push r 2; push r 3; xs <- IORef.readIORef r; return (length xs) }")))
+  (list "IO" 3))
+
+(hk-test
+  "accumulate.hs — pushAll preserves reverse order"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-accumulate-source
+        "main = do { r <- IORef.newIORef []; pushAll r [1,2,3,4]; xs <- IORef.readIORef r; return xs }")))
+  (list
+    "IO"
+    (list ":" 4 (list ":" 3 (list ":" 2 (list ":" 1 (list "[]")))))))
+
+(hk-test
+  "accumulate.hs — readReversed gives original order"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-accumulate-source
+        "main = do { r <- IORef.newIORef []; pushAll r [10,20,30]; readReversed r }")))
+  (list "IO" (list ":" 10 (list ":" 20 (list ":" 30 (list "[]"))))))
+
+(hk-test
+  "accumulate.hs — doubleEach maps then accumulates"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-accumulate-source
+        "main = do { r <- IORef.newIORef []; doubleEach r [1,2,3]; readReversed r }")))
+  (list "IO" (list ":" 2 (list ":" 4 (list ":" 6 (list "[]"))))))
+
+(hk-test
+  "accumulate.hs — sum into Int IORef"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-accumulate-source
+        "main = do { r <- IORef.newIORef 0; sumIntoRef r [1,2,3,4,5]; v <- IORef.readIORef r; return v }")))
+  (list "IO" 15))
+
+(hk-test
+  "accumulate.hs — empty list leaves ref untouched"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-accumulate-source
+        "main = do { r <- IORef.newIORef [99]; pushAll r []; xs <- IORef.readIORef r; return xs }")))
+  (list "IO" (list ":" 99 (list "[]"))))
+
+(hk-test
+  "accumulate.hs — pushAll then sumIntoRef on the same input"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-accumulate-source
+        "main = do { r <- IORef.newIORef 0; sumIntoRef r [10,20,30,40]; v <- IORef.readIORef r; return v }")))
+  (list "IO" 100))
+
+(hk-test
+  "accumulate.hs — accumulate results from a recursive helper"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-accumulate-source
+        "squaresUpTo r 0 = return ()\nsquaresUpTo r n = do { push r (n * n); squaresUpTo r (n - 1) }\nmain = do { r <- IORef.newIORef []; squaresUpTo r 4; readReversed r }")))
+  (list
+    "IO"
+    (list ":" 16 (list ":" 9 (list ":" 4 (list ":" 1 (list "[]")))))))
--- a/lib/haskell/tests/program-caesar.sx
+++ b/lib/haskell/tests/program-caesar.sx
@@ -0,0 +1,80 @@
+;; caesar.hs — Caesar cipher.
+;; Source: https://rosettacode.org/wiki/Caesar_cipher#Haskell (adapted).
+;;
+;; Exercises chr, ord, isUpper, isLower, mod, string pattern matching
+;; (x:xs) over a String (which is now a [Char] string view), and map
+;; from the Phase 7 string=[Char] foundation.
+
+(define
+  hk-prog-val
+  (fn
+    (src name)
+    (hk-deep-force (get (hk-eval-program (hk-core src)) name))))
+
+(define
+  hk-as-list
+  (fn
+    (xs)
+    (cond
+      ((and (list? xs) (= (first xs) "[]")) (list))
+      ((and (list? xs) (= (first xs) ":"))
+        (cons (nth xs 1) (hk-as-list (nth xs 2))))
+      (:else xs))))
+
+(define
+  hk-caesar-source
+  "shift n c = if isUpper c\n              then chr (mod ((ord c) - 65 + n) 26 + 65)\n              else if isLower c\n                     then chr (mod ((ord c) - 97 + n) 26 + 97)\n                     else chr c\n\ncaesarRec n []     = []\ncaesarRec n (x:xs) = shift n x : caesarRec n xs\n\ncaesarMap n s = map (shift n) s\n")
+
+(hk-test
+  "caesar.hs — caesarRec 3 \"ABC\" = DEF"
+  (hk-as-list
+    (hk-prog-val (str hk-caesar-source "r = caesarRec 3 \"ABC\"\n") "r"))
+  (list "D" "E" "F"))
+
+(hk-test
+  "caesar.hs — caesarRec 13 \"Hello\" = Uryyb"
+  (hk-as-list
+    (hk-prog-val (str hk-caesar-source "r = caesarRec 13 \"Hello\"\n") "r"))
+  (list "U" "r" "y" "y" "b"))
+
+(hk-test
+  "caesar.hs — caesarRec 1 \"AZ\" wraps to BA"
+  (hk-as-list
+    (hk-prog-val (str hk-caesar-source "r = caesarRec 1 \"AZ\"\n") "r"))
+  (list "B" "A"))
+
+(hk-test
+  "caesar.hs — caesarRec 0 \"World\" identity"
+  (hk-as-list
+    (hk-prog-val (str hk-caesar-source "r = caesarRec 0 \"World\"\n") "r"))
+  (list "W" "o" "r" "l" "d"))
+
+(hk-test
+  "caesar.hs — caesarRec preserves punctuation"
+  (hk-as-list
+    (hk-prog-val (str hk-caesar-source "r = caesarRec 3 \"Hi!\"\n") "r"))
+  (list "K" "l" "!"))
+
+(hk-test
+  "caesar.hs — caesarMap 3 \"abc\" via map"
+  (hk-as-list
+    (hk-prog-val (str hk-caesar-source "r = caesarMap 3 \"abc\"\n") "r"))
+  (list "d" "e" "f"))
+
+(hk-test
+  "caesar.hs — caesarMap 13 round-trips with caesarMap 13"
+  (hk-as-list
+    (hk-prog-val
+      (str
+        hk-caesar-source
+        "r = caesarMap 13 (foldr (\\c acc -> c : acc) [] (caesarMap 13 \"Hello\"))\n")
+      "r"))
+  (list "H" "e" "l" "l" "o"))
+
+(hk-test
+  "caesar.hs — caesarRec 25 \"AB\" = ZA"
+  (hk-as-list
+    (hk-prog-val (str hk-caesar-source "r = caesarRec 25 \"AB\"\n") "r"))
+  (list "Z" "A"))
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-config.sx
+++ b/lib/haskell/tests/program-config.sx
@@ -0,0 +1,63 @@
+;; config.hs — multi-field config record; partial update; defaultConfig
+;;            constant.
+;;
+;; Exercises Phase 14: 4-field record, defaultConfig as a CAF, partial
+;; updates that change one or two fields, accessors over derived configs.
+
+(define
+  hk-config-source
+  "data Config = Config { host :: String, port :: Int, retries :: Int, debug :: Bool } deriving (Show)\n\ndefaultConfig = Config { host = \"localhost\", port = 8080, retries = 3, debug = False }\n\ndevConfig = defaultConfig { debug = True }\nremoteConfig = defaultConfig { host = \"api.example.com\", port = 443 }\n")
+
+(hk-test
+  "config.hs — defaultConfig host"
+  (hk-deep-force (hk-run (str hk-config-source "main = host defaultConfig")))
+  "localhost")
+
+(hk-test
+  "config.hs — defaultConfig port"
+  (hk-deep-force (hk-run (str hk-config-source "main = port defaultConfig")))
+  8080)
+
+(hk-test
+  "config.hs — defaultConfig retries"
+  (hk-deep-force
+    (hk-run (str hk-config-source "main = retries defaultConfig")))
+  3)
+
+(hk-test
+  "config.hs — devConfig flips debug"
+  (hk-deep-force (hk-run (str hk-config-source "main = debug devConfig")))
+  (list "True"))
+
+(hk-test
+  "config.hs — devConfig preserves host"
+  (hk-deep-force (hk-run (str hk-config-source "main = host devConfig")))
+  "localhost")
+
+(hk-test
+  "config.hs — devConfig preserves port"
+  (hk-deep-force (hk-run (str hk-config-source "main = port devConfig")))
+  8080)
+
+(hk-test
+  "config.hs — remoteConfig new host"
+  (hk-deep-force (hk-run (str hk-config-source "main = host remoteConfig")))
+  "api.example.com")
+
+(hk-test
+  "config.hs — remoteConfig new port"
+  (hk-deep-force (hk-run (str hk-config-source "main = port remoteConfig")))
+  443)
+
+(hk-test
+  "config.hs — remoteConfig preserves retries"
+  (hk-deep-force
+    (hk-run (str hk-config-source "main = retries remoteConfig")))
+  3)
+
+(hk-test
+  "config.hs — remoteConfig preserves debug"
+  (hk-deep-force (hk-run (str hk-config-source "main = debug remoteConfig")))
+  (list "False"))
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-counter.sx
+++ b/lib/haskell/tests/program-counter.sx
@@ -0,0 +1,66 @@
+;; counter.hs — IORef-backed mutable counter (Phase 15 conformance).
+
+(define
+  hk-counter-source
+  "import qualified Data.IORef as IORef\n\ncount :: IORef Int -> Int -> IO ()\ncount r 0 = return ()\ncount r n = do\n  IORef.modifyIORef r (\\x -> x + 1)\n  count r (n - 1)\n\ncountBy :: IORef Int -> Int -> Int -> IO ()\ncountBy r step 0 = return ()\ncountBy r step n = do\n  IORef.modifyIORef r (\\x -> x + step)\n  countBy r step (n - 1)\n\nnewCounter :: Int -> IO (IORef Int)\nnewCounter v = IORef.newIORef v\n\nbumpAndRead :: IORef Int -> IO Int\nbumpAndRead r = do\n  IORef.modifyIORef r (\\x -> x + 1)\n  IORef.readIORef r\n\n")
+
+(hk-test
+  "counter.hs — start at 0, count 5 ⇒ 5"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-counter-source
+        "main = do { r <- newCounter 0; count r 5; v <- IORef.readIORef r; return v }")))
+  (list "IO" 5))
+
+(hk-test
+  "counter.hs — start at 100, count 10 ⇒ 110"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-counter-source
+        "main = do { r <- newCounter 100; count r 10; v <- IORef.readIORef r; return v }")))
+  (list "IO" 110))
+
+(hk-test
+  "counter.hs — countBy step 5, n 4 ⇒ 20"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-counter-source
+        "main = do { r <- newCounter 0; countBy r 5 4; v <- IORef.readIORef r; return v }")))
+  (list "IO" 20))
+
+(hk-test
+  "counter.hs — bumpAndRead returns updated value"
+  (hk-deep-force
+    (hk-run
+      (str hk-counter-source "main = do { r <- newCounter 41; bumpAndRead r }")))
+  (list "IO" 42))
+
+(hk-test
+  "counter.hs — count then countBy compose"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-counter-source
+        "main = do { r <- newCounter 0; count r 3; countBy r 10 2; v <- IORef.readIORef r; return v }")))
+  (list "IO" 23))
+
+(hk-test
+  "counter.hs — two independent counters"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-counter-source
+        "main = do { a <- newCounter 0; b <- newCounter 0; count a 7; countBy b 100 2; va <- IORef.readIORef a; vb <- IORef.readIORef b; return (va + vb) }")))
+  (list "IO" 207))
+
+(hk-test
+  "counter.hs — modifyIORef' (strict) variant"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-counter-source
+        "tick r 0 = return ()\ntick r n = do { IORef.modifyIORef' r (\\x -> x + 1); tick r (n - 1) }\nmain = do { r <- newCounter 0; tick r 50; v <- IORef.readIORef r; return v }")))
+  (list "IO" 50))
--- a/lib/haskell/tests/program-mapgraph.sx
+++ b/lib/haskell/tests/program-mapgraph.sx
@@ -0,0 +1,46 @@
+;; mapgraph.hs — adjacency-list using Data.Map (BFS-style traversal).
+;;
+;; Exercises Phase 11: `import qualified Data.Map as Map`, `Map.empty`,
+;; `Map.insert`, `Map.lookup`, `Map.findWithDefault`. Adjacency lists are
+;; stored as `Map Int [Int]`; `neighbors` does a default-empty lookup.
+
+(define
+  hk-mapgraph-source
+  "import qualified Data.Map as Map\n\nemptyG = Map.empty\n\naddEdge u v g = Map.insertWith add u [v] g\n  where add new old = new ++ old\n\nbuild = addEdge 1 2 (addEdge 1 3 (addEdge 2 4 (addEdge 3 4 (addEdge 4 5 emptyG))))\n\nneighbors n g = Map.findWithDefault [] n g\n")
+
+(hk-test
+  "mapgraph.hs — neighbors of 1"
+  (hk-deep-force
+    (hk-run (str hk-mapgraph-source "main = neighbors 1 build\n")))
+  (list ":" 2 (list ":" 3 (list "[]"))))
+
+(hk-test
+  "mapgraph.hs — neighbors of 4"
+  (hk-deep-force
+    (hk-run (str hk-mapgraph-source "main = neighbors 4 build\n")))
+  (list ":" 5 (list "[]")))
+
+(hk-test
+  "mapgraph.hs — neighbors of 5 (leaf, no entry) defaults to []"
+  (hk-deep-force
+    (hk-run (str hk-mapgraph-source "main = neighbors 5 build\n")))
+  (list "[]"))
+
+(hk-test
+  "mapgraph.hs — neighbors of 99 (absent) defaults to []"
+  (hk-deep-force
+    (hk-run (str hk-mapgraph-source "main = neighbors 99 build\n")))
+  (list "[]"))
+
+(hk-test
+  "mapgraph.hs — Map.member 1"
+  (hk-deep-force
+    (hk-run (str hk-mapgraph-source "main = Map.member 1 build\n")))
+  (list "True"))
+
+(hk-test
+  "mapgraph.hs — Map.size = 4 source nodes"
+  (hk-deep-force (hk-run (str hk-mapgraph-source "main = Map.size build\n")))
+  4)
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-newton.sx
+++ b/lib/haskell/tests/program-newton.sx
@@ -0,0 +1,49 @@
+;; newton.hs — Newton's method for square root.
+;; Source: classic numerical analysis exercise.
+;;
+;; Exercises Phase 10: `Float`, `abs`, `/`, iteration via `until`.
+
+(define
+  hk-prog-val
+  (fn
+    (src name)
+    (hk-deep-force (get (hk-eval-program (hk-core src)) name))))
+
+(define
+  hk-newton-source
+  "improve x guess = (guess + x / guess) / 2\n\ngoodEnough x guess = abs (guess * guess - x) < 0.0001\n\nnewtonSqrt x = newtonHelp x 1.0\n\nnewtonHelp x guess = if goodEnough x guess\n                       then guess\n                       else newtonHelp x (improve x guess)\n")
+
+(hk-test
+  "newton.hs — newtonSqrt 4 ≈ 2"
+  (hk-prog-val
+    (str hk-newton-source "r = abs (newtonSqrt 4.0 - 2.0) < 0.001\n")
+    "r")
+  (list "True"))
+
+(hk-test
+  "newton.hs — newtonSqrt 9 ≈ 3"
+  (hk-prog-val
+    (str hk-newton-source "r = abs (newtonSqrt 9.0 - 3.0) < 0.001\n")
+    "r")
+  (list "True"))
+
+(hk-test
+  "newton.hs — newtonSqrt 2 ≈ 1.41421"
+  (hk-prog-val
+    (str hk-newton-source "r = abs (newtonSqrt 2.0 - 1.41421) < 0.001\n")
+    "r")
+  (list "True"))
+
+(hk-test
+  "newton.hs — improve converges (one step)"
+  (hk-prog-val (str hk-newton-source "r = improve 4.0 1.0\n") "r")
+  2.5)
+
+(hk-test
+  "newton.hs — newtonSqrt 100 ≈ 10"
+  (hk-prog-val
+    (str hk-newton-source "r = abs (newtonSqrt 100.0 - 10.0) < 0.001\n")
+    "r")
+  (list "True"))
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-partial.sx
+++ b/lib/haskell/tests/program-partial.sx
@@ -0,0 +1,58 @@
+;; partial.hs — exercises Phase 9 partial functions caught at the top level.
+;;
+;; Each program calls a partial function on bad input; hk-run-io catches the
+;; raise and appends the error message to io-lines so tests can inspect.
+
+(hk-test
+  "partial.hs — main = print (head [])"
+  (let
+    ((lines (hk-run-io "main = print (head [])")))
+    (>= (index-of (str lines) "Prelude.head: empty list") 0))
+  true)
+
+(hk-test
+  "partial.hs — main = print (tail [])"
+  (let
+    ((lines (hk-run-io "main = print (tail [])")))
+    (>= (index-of (str lines) "Prelude.tail: empty list") 0))
+  true)
+
+(hk-test
+  "partial.hs — main = print (fromJust Nothing)"
+  (let
+    ((lines (hk-run-io "main = print (fromJust Nothing)")))
+    (>= (index-of (str lines) "Maybe.fromJust: Nothing") 0))
+  true)
+
+(hk-test
+  "partial.hs — putStrLn before error preserves prior output"
+  (let
+    ((lines (hk-run-io "main = do { putStrLn \"step 1\"; putStrLn (show (head [])); putStrLn \"never\" }")))
+    (and
+      (>= (index-of (str lines) "step 1") 0)
+      (>= (index-of (str lines) "Prelude.head: empty list") 0)
+      (= (index-of (str lines) "never") -1)))
+  true)
+
+(hk-test
+  "partial.hs — undefined as IO action"
+  (let
+    ((lines (hk-run-io "main = print undefined")))
+    (>= (index-of (str lines) "Prelude.undefined") 0))
+  true)
+
+(hk-test
+  "partial.hs — catches error from a user-thrown error"
+  (let
+    ((lines (hk-run-io "main = error \"boom from main\"")))
+    (>= (index-of (str lines) "boom from main") 0))
+  true)
+
+;; Negative case: when no error is raised, io-lines doesn't contain
+;; "Prelude" prefixes from our error path.
+(hk-test
+  "partial.hs — happy path: head [42] succeeds, no error in output"
+  (hk-run-io "main = print (head [42])")
+  (list "42"))
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-person.sx
+++ b/lib/haskell/tests/program-person.sx
@@ -0,0 +1,51 @@
+;; person.hs — record type with accessors, update, deriving Show.
+;;
+;; Exercises Phase 14: data with record syntax, accessor functions,
+;; record creation, record update, deriving Show on a record.
+
+(define
+  hk-person-source
+  "data Person = Person { name :: String, age :: Int } deriving (Show)\n\nalice = Person { name = \"alice\", age = 30 }\nbob = Person { name = \"bob\", age = 25 }\n\nbirthday p = p { age = age p + 1 }\n")
+
+(hk-test
+  "person.hs — alice's name"
+  (hk-deep-force (hk-run (str hk-person-source "main = name alice")))
+  "alice")
+
+(hk-test
+  "person.hs — alice's age"
+  (hk-deep-force (hk-run (str hk-person-source "main = age alice")))
+  30)
+
+(hk-test
+  "person.hs — birthday adds one year"
+  (hk-deep-force
+    (hk-run (str hk-person-source "main = age (birthday alice)")))
+  31)
+
+(hk-test
+  "person.hs — birthday preserves name"
+  (hk-deep-force
+    (hk-run (str hk-person-source "main = name (birthday alice)")))
+  "alice")
+
+(hk-test
+  "person.hs — show alice"
+  (hk-deep-force (hk-run (str hk-person-source "main = show alice")))
+  "Person \"alice\" 30")
+
+(hk-test
+  "person.hs — bob has different name"
+  (hk-deep-force (hk-run (str hk-person-source "main = name bob")))
+  "bob")
+
+(hk-test
+  "person.hs — pattern match in function"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-person-source
+        "greet (Person { name = n }) = \"Hi, \" ++ n\nmain = greet alice")))
+  "Hi, alice")
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-runlength-str.sx
+++ b/lib/haskell/tests/program-runlength-str.sx
@@ -0,0 +1,83 @@
+;; runlength-str.hs — run-length encoding on a String.
+;; Source: https://rosettacode.org/wiki/Run-length_encoding#Haskell (adapted).
+;;
+;; Exercises String pattern matching `(x:xs)`, `span` over a string view,
+;; tuple construction `(Int, Char)`, character equality, and tuple-in-cons
+;; patterns `((n, c) : rest)` — all enabled by Phase 7 string=[Char].
+
+(define
+  hk-prog-val
+  (fn
+    (src name)
+    (hk-deep-force (get (hk-eval-program (hk-core src)) name))))
+
+(define
+  hk-as-list
+  (fn
+    (xs)
+    (cond
+      ((and (list? xs) (= (first xs) "[]")) (list))
+      ((and (list? xs) (= (first xs) ":"))
+        (cons (nth xs 1) (hk-as-list (nth xs 2))))
+      (:else xs))))
+
+(define
+  hk-rle-source
+  "encodeRL []     = []\nencodeRL (x:xs) = let (same, rest) = span eqX xs\n                      eqX y         = y == x\n                  in (1 + length same, x) : encodeRL rest\n\nreplicateRL 0 _ = []\nreplicateRL n c = c : replicateRL (n - 1) c\n\ndecodeRL []                = []\ndecodeRL ((n, c) : rest)   = replicateRL n c ++ decodeRL rest\n")
+
+(hk-test
+  "rle.hs — encodeRL [] = []"
+  (hk-as-list (hk-prog-val (str hk-rle-source "r = encodeRL \"\"\n") "r"))
+  (list))
+
+(hk-test
+  "rle.hs — length (encodeRL \"aabbbcc\") = 3"
+  (hk-prog-val (str hk-rle-source "r = length (encodeRL \"aabbbcc\")\n") "r")
+  3)
+
+(hk-test
+  "rle.hs — map fst (encodeRL \"aabbbcc\") = [2,3,2]"
+  (hk-as-list
+    (hk-prog-val (str hk-rle-source "r = map fst (encodeRL \"aabbbcc\")\n") "r"))
+  (list 2 3 2))
+
+(hk-test
+  "rle.hs — map snd (encodeRL \"aabbbcc\") = [97,98,99]"
+  (hk-as-list
+    (hk-prog-val (str hk-rle-source "r = map snd (encodeRL \"aabbbcc\")\n") "r"))
+  (list 97 98 99))
+
+(hk-test
+  "rle.hs — counts of encodeRL \"aabbbccddddee\" = [2,3,2,4,2]"
+  (hk-as-list
+    (hk-prog-val
+      (str hk-rle-source "r = map fst (encodeRL \"aabbbccddddee\")\n")
+      "r"))
+  (list 2 3 2 4 2))
+
+(hk-test
+  "rle.hs — chars of encodeRL \"aabbbccddddee\" = [97,98,99,100,101]"
+  (hk-as-list
+    (hk-prog-val
+      (str hk-rle-source "r = map snd (encodeRL \"aabbbccddddee\")\n")
+      "r"))
+  (list 97 98 99 100 101))
+
+(hk-test
+  "rle.hs — singleton encodeRL \"x\""
+  (hk-as-list
+    (hk-prog-val (str hk-rle-source "r = map fst (encodeRL \"x\")\n") "r"))
+  (list 1))
+
+(hk-test
+  "rle.hs — decodeRL round-trip preserves \"aabbbcc\""
+  (hk-as-list
+    (hk-prog-val (str hk-rle-source "r = decodeRL (encodeRL \"aabbbcc\")\n") "r"))
+  (list 97 97 98 98 98 99 99))
+
+(hk-test
+  "rle.hs — replicateRL 4 65 = [65,65,65,65]"
+  (hk-as-list (hk-prog-val (str hk-rle-source "r = replicateRL 4 65\n") "r"))
+  (list 65 65 65 65))
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-safediv.sx
+++ b/lib/haskell/tests/program-safediv.sx
@@ -0,0 +1,80 @@
+;; safediv.hs — safe division using catch (Phase 16 conformance).
+
+(define
+  hk-safediv-source
+  "safeDiv :: Int -> Int -> IO Int
+safeDiv _ 0 = throwIO (SomeException \"division by zero\")
+safeDiv x y = return (x `div` y)
+
+guarded :: Int -> Int -> IO Int
+guarded x y = catch (safeDiv x y) (\\(SomeException _) -> return 0)
+
+reason :: Int -> Int -> IO String
+reason x y = catch (safeDiv x y `seq` return \"ok\")
+  (\\(SomeException m) -> return m)
+
+bothBranches :: Int -> Int -> IO Int
+bothBranches x y = do
+  v <- catch (safeDiv x y) (\\(SomeException _) -> return (-1))
+  return (v + 100)
+
+")
+
+(hk-test
+  "safediv.hs — divide by non-zero"
+  (hk-deep-force
+    (hk-run
+      (str hk-safediv-source "main = guarded 10 2")))
+  (list "IO" 5))
+
+(hk-test
+  "safediv.hs — divide by zero returns 0"
+  (hk-deep-force
+    (hk-run
+      (str hk-safediv-source "main = guarded 10 0")))
+  (list "IO" 0))
+
+(hk-test
+  "safediv.hs — divide by zero — reason captured"
+  (hk-deep-force
+    (hk-run
+      (str hk-safediv-source "main = catch (safeDiv 1 0) (\\(SomeException m) -> return 0) >> reason 1 0")))
+  (list "IO" "division by zero"))
+
+(hk-test
+  "safediv.hs — bothBranches success path"
+  (hk-deep-force
+    (hk-run
+      (str hk-safediv-source "main = bothBranches 8 2")))
+  (list "IO" 104))
+
+(hk-test
+  "safediv.hs — bothBranches failure path"
+  (hk-deep-force
+    (hk-run
+      (str hk-safediv-source "main = bothBranches 8 0")))
+  (list "IO" 99))
+
+(hk-test
+  "safediv.hs — chained safeDiv with catch"
+  (hk-deep-force
+    (hk-run
+      (str hk-safediv-source
+        "main = do { a <- guarded 20 4; b <- guarded 7 0; return (a + b) }")))
+  (list "IO" 5))
+
+(hk-test
+  "safediv.hs — try then bind through Either"
+  (hk-deep-force
+    (hk-run
+      (str hk-safediv-source
+        "main = do { r <- try (safeDiv 1 0); case r of { Right v -> return v; Left (SomeException m) -> return 999 } }")))
+  (list "IO" 999))
+
+(hk-test
+  "safediv.hs — handle (flip catch)"
+  (hk-deep-force
+    (hk-run
+      (str hk-safediv-source
+        "main = handle (\\(SomeException _) -> return 0) (safeDiv 5 0)")))
+  (list "IO" 0))
--- a/lib/haskell/tests/program-setops.sx
+++ b/lib/haskell/tests/program-setops.sx
@@ -0,0 +1,61 @@
+;; setops.hs — set union/intersection/difference on integer sets.
+;;
+;; Exercises Phase 12: `import qualified Data.Set as Set`, all three
+;; combining operations + isSubsetOf.
+
+(define
+  hk-setops-source
+  "import qualified Data.Set as Set\n\ns1 = Set.insert 1 (Set.insert 2 (Set.insert 3 Set.empty))\ns2 = Set.insert 3 (Set.insert 4 (Set.insert 5 Set.empty))\ns3 = Set.insert 1 (Set.insert 2 Set.empty)\n")
+
+(hk-test
+  "setops.hs — union size = 5"
+  (hk-deep-force
+    (hk-run (str hk-setops-source "main = Set.size (Set.union s1 s2)\n")))
+  5)
+
+(hk-test
+  "setops.hs — intersection size = 1"
+  (hk-deep-force
+    (hk-run
+      (str hk-setops-source "main = Set.size (Set.intersection s1 s2)\n")))
+  1)
+
+(hk-test
+  "setops.hs — intersection contains 3"
+  (hk-deep-force
+    (hk-run
+      (str hk-setops-source "main = Set.member 3 (Set.intersection s1 s2)\n")))
+  (list "True"))
+
+(hk-test
+  "setops.hs — difference s1 s2 size = 2"
+  (hk-deep-force
+    (hk-run (str hk-setops-source "main = Set.size (Set.difference s1 s2)\n")))
+  2)
+
+(hk-test
+  "setops.hs — difference doesn't contain shared key"
+  (hk-deep-force
+    (hk-run
+      (str hk-setops-source "main = Set.member 3 (Set.difference s1 s2)\n")))
+  (list "False"))
+
+(hk-test
+  "setops.hs — s3 is subset of s1"
+  (hk-deep-force
+    (hk-run (str hk-setops-source "main = Set.isSubsetOf s3 s1\n")))
+  (list "True"))
+
+(hk-test
+  "setops.hs — s1 not subset of s3"
+  (hk-deep-force
+    (hk-run (str hk-setops-source "main = Set.isSubsetOf s1 s3\n")))
+  (list "False"))
+
+(hk-test
+  "setops.hs — empty set is subset of anything"
+  (hk-deep-force
+    (hk-run (str hk-setops-source "main = Set.isSubsetOf Set.empty s1\n")))
+  (list "True"))
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-shapes.sx
+++ b/lib/haskell/tests/program-shapes.sx
@@ -0,0 +1,40 @@
+;; shapes.hs — class Area with a default perimeter, two instances
+;;             using where-local helpers.
+;;
+;; Exercises Phase 13: class default method (perimeter), instance
+;; methods that use `where`-bindings.
+
+(define
+  hk-shapes-source
+  "class Shape a where\n  area :: a -> Int\n  perimeter :: a -> Int\n  perimeter x = quadrilateral x\n    where quadrilateral y = 2 * (sideA y + sideB y)\n          sideA z = 1\n          sideB z = 1\n\ndata Square = Square Int\ndata Rect = Rect Int Int\n\ninstance Shape Square where\n  area (Square s) = s * s\n  perimeter (Square s) = 4 * s\n\ninstance Shape Rect where\n  area (Rect w h) = w * h\n  perimeter (Rect w h) = peri\n    where peri = 2 * (w + h)\n")
+
+(hk-test
+  "shapes.hs — area of Square 5 = 25"
+  (hk-deep-force (hk-run (str hk-shapes-source "main = area (Square 5)\n")))
+  25)
+
+(hk-test
+  "shapes.hs — perimeter of Square 5 = 20"
+  (hk-deep-force
+    (hk-run (str hk-shapes-source "main = perimeter (Square 5)\n")))
+  20)
+
+(hk-test
+  "shapes.hs — area of Rect 3 4 = 12"
+  (hk-deep-force (hk-run (str hk-shapes-source "main = area (Rect 3 4)\n")))
+  12)
+
+(hk-test
+  "shapes.hs — perimeter of Rect 3 4 = 14 (via where-bound)"
+  (hk-deep-force
+    (hk-run (str hk-shapes-source "main = perimeter (Rect 3 4)\n")))
+  14)
+
+(hk-test
+  "shapes.hs — Square sums area + perimeter"
+  (hk-deep-force
+    (hk-run
+      (str hk-shapes-source "main = area (Square 4) + perimeter (Square 4)\n")))
+  32)
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-showadt.sx
+++ b/lib/haskell/tests/program-showadt.sx
@@ -0,0 +1,45 @@
+;; showadt.hs — `deriving (Show)` on a multi-constructor recursive ADT.
+;; Source: classic exposition example, e.g. Real World Haskell ch.6.
+;;
+;; Exercises Phase 8: `deriving (Show)` on an ADT whose constructors recurse
+;; into themselves; precedence-based paren wrapping for nested arguments;
+;; `print` from the prelude (which is `putStrLn (show x)`).
+
+(define
+  hk-showadt-source
+  "data Expr = Lit Int | Add Expr Expr | Mul Expr Expr deriving (Show)\n\nmain = do\n  print (Lit 3)\n  print (Add (Lit 1) (Lit 2))\n  print (Mul (Lit 3) (Add (Lit 4) (Lit 5)))\n")
+
+(hk-test
+  "showadt.hs — main prints three lines"
+  (hk-run-io hk-showadt-source)
+  (list "Lit 3" "Add (Lit 1) (Lit 2)" "Mul (Lit 3) (Add (Lit 4) (Lit 5))"))
+
+(hk-test
+  "showadt.hs — show Lit 3"
+  (hk-deep-force
+    (hk-run
+      "data Expr = Lit Int | Add Expr Expr | Mul Expr Expr deriving (Show)\nmain = show (Lit 3)"))
+  "Lit 3")
+
+(hk-test
+  "showadt.hs — show Add wraps both args"
+  (hk-deep-force
+    (hk-run
+      "data Expr = Lit Int | Add Expr Expr | Mul Expr Expr deriving (Show)\nmain = show (Add (Lit 1) (Lit 2))"))
+  "Add (Lit 1) (Lit 2)")
+
+(hk-test
+  "showadt.hs — fully nested Mul of Adds"
+  (hk-deep-force
+    (hk-run
+      "data Expr = Lit Int | Add Expr Expr | Mul Expr Expr deriving (Show)\nmain = show (Mul (Add (Lit 1) (Lit 2)) (Add (Lit 3) (Lit 4)))"))
+  "Mul (Add (Lit 1) (Lit 2)) (Add (Lit 3) (Lit 4))")
+
+(hk-test
+  "showadt.hs — Lit with negative literal wraps int in parens"
+  (hk-deep-force
+    (hk-run
+      "data Expr = Lit Int | Add Expr Expr | Mul Expr Expr deriving (Show)\nmain = show (Lit (negate 7))"))
+  "Lit (-7)")
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-showio.sx
+++ b/lib/haskell/tests/program-showio.sx
@@ -0,0 +1,36 @@
+;; showio.hs — `print` on various types inside a `do` block.
+;;
+;; Exercises Phase 8 `print x = putStrLn (show x)` and the IO monad's
+;; statement sequencing. Each `print` produces one io-line.
+
+(define
+  hk-showio-source
+  "main = do\n  print 42\n  print True\n  print False\n  print [1,2,3]\n  print (1, 2)\n  print (Just 5)\n  print Nothing\n  print \"hello\"\n")
+
+(hk-test
+  "showio.hs — main produces 8 lines, all show-formatted"
+  (hk-run-io hk-showio-source)
+  (list "42" "True" "False" "[1,2,3]" "(1,2)" "Just 5" "Nothing" "\"hello\""))
+
+(hk-test
+  "showio.hs — print Int alone"
+  (hk-run-io "main = print 42")
+  (list "42"))
+
+(hk-test
+  "showio.hs — print list of Maybe"
+  (hk-run-io "main = print [Just 1, Nothing, Just 3]")
+  (list "[Just 1,Nothing,Just 3]"))
+
+(hk-test
+  "showio.hs — print nested tuple"
+  (hk-run-io "main = print ((1, 2), (3, 4))")
+  (list "((1,2),(3,4))"))
+
+(hk-test
+  "showio.hs — print derived ADT inside do"
+  (hk-run-io
+    "data Color = Red | Green | Blue deriving (Show)\nmain = do { print Red; print Green; print Blue }")
+  (list "Red" "Green" "Blue"))
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-statistics.sx
+++ b/lib/haskell/tests/program-statistics.sx
@@ -0,0 +1,45 @@
+;; statistics.hs — mean, variance, std-dev on a [Double].
+;; Source: classic textbook example.
+;;
+;; Exercises Phase 10: `fromIntegral`, `/`, `sqrt`, list ops on `[Double]`.
+
+(define
+  hk-prog-val
+  (fn
+    (src name)
+    (hk-deep-force (get (hk-eval-program (hk-core src)) name))))
+
+(define
+  hk-stats-source
+  "mean xs = sum xs / fromIntegral (length xs)\n\nvariance xs = let m = mean xs\n                  sqDiff x = (x - m) * (x - m)\n              in sum (map sqDiff xs) / fromIntegral (length xs)\n\nstdDev xs = sqrt (variance xs)\n")
+
+(hk-test
+  "statistics.hs — mean [1,2,3,4,5] = 3"
+  (hk-prog-val (str hk-stats-source "r = mean [1.0,2.0,3.0,4.0,5.0]\n") "r")
+  3)
+
+(hk-test
+  "statistics.hs — mean [10,20,30] = 20"
+  (hk-prog-val (str hk-stats-source "r = mean [10.0,20.0,30.0]\n") "r")
+  20)
+
+(hk-test
+  "statistics.hs — variance [2,4,4,4,5,5,7,9] = 4"
+  (hk-prog-val
+    (str hk-stats-source "r = variance [2.0,4.0,4.0,4.0,5.0,5.0,7.0,9.0]\n")
+    "r")
+  4)
+
+(hk-test
+  "statistics.hs — stdDev [2,4,4,4,5,5,7,9] = 2"
+  (hk-prog-val
+    (str hk-stats-source "r = stdDev [2.0,4.0,4.0,4.0,5.0,5.0,7.0,9.0]\n")
+    "r")
+  2)
+
+(hk-test
+  "statistics.hs — variance of constant list = 0"
+  (hk-prog-val (str hk-stats-source "r = variance [5.0,5.0,5.0,5.0]\n") "r")
+  0)
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-trycatch.sx
+++ b/lib/haskell/tests/program-trycatch.sx
@@ -0,0 +1,95 @@
+;; trycatch.hs — try pattern: branch on Left/Right (Phase 16 conformance).
+
+(define
+  hk-trycatch-source
+  "parseInt :: String -> IO Int
+parseInt \"zero\" = return 0
+parseInt \"one\"  = return 1
+parseInt \"two\"  = return 2
+parseInt s = throwIO (SomeException (\"unknown: \" ++ s))
+
+describe :: Either SomeException Int -> String
+describe (Right v) = \"got \" ++ show v
+describe (Left (SomeException m)) = \"err: \" ++ m
+
+trial :: String -> IO String
+trial s = do
+  r <- try (parseInt s)
+  return (describe r)
+
+run3 :: String -> String -> String -> IO [String]
+run3 a b c = do
+  ra <- trial a
+  rb <- trial b
+  rc <- trial c
+  return [ra, rb, rc]
+
+")
+
+(hk-test
+  "trycatch.hs — Right branch"
+  (hk-deep-force
+    (hk-run
+      (str hk-trycatch-source "main = trial \"one\"")))
+  (list "IO" "got 1"))
+
+(hk-test
+  "trycatch.hs — Left branch with message"
+  (hk-deep-force
+    (hk-run
+      (str hk-trycatch-source "main = trial \"banana\"")))
+  (list "IO" "err: unknown: banana"))
+
+(hk-test
+  "trycatch.hs — chain over three inputs, all good"
+  (hk-deep-force
+    (hk-run
+      (str hk-trycatch-source "main = run3 \"zero\" \"one\" \"two\"")))
+  (list "IO"
+    (list ":" "got 0"
+      (list ":" "got 1"
+        (list ":" "got 2"
+          (list "[]"))))))
+
+(hk-test
+  "trycatch.hs — chain over three inputs, mixed"
+  (hk-deep-force
+    (hk-run
+      (str hk-trycatch-source "main = run3 \"zero\" \"qux\" \"two\"")))
+  (list "IO"
+    (list ":" "got 0"
+      (list ":" "err: unknown: qux"
+        (list ":" "got 2"
+          (list "[]"))))))
+
+(hk-test
+  "trycatch.hs — Left from throwIO carries message"
+  (hk-deep-force
+    (hk-run
+      (str hk-trycatch-source
+        "main = do { r <- try (throwIO (SomeException \"explicit\")); return (describe r) }")))
+  (list "IO" "err: explicit"))
+
+(hk-test
+  "trycatch.hs — Right preserves the int"
+  (hk-deep-force
+    (hk-run
+      (str hk-trycatch-source
+        "main = do { r <- try (return 42); return (describe r) }")))
+  (list "IO" "got 42"))
+
+(hk-test
+  "trycatch.hs — pattern-bind on Right inside do"
+  (hk-deep-force
+    (hk-run
+      (str hk-trycatch-source
+        "main = do { Right v <- try (parseInt \"two\"); return (v + 100) }")))
+  (list "IO" 102))
+
+(hk-test
+  "trycatch.hs — handle alias on parseInt failure"
+  (hk-deep-force
+    (hk-run
+      (str hk-trycatch-source
+        "main = handle (\\(SomeException m) -> return (\"caught: \" ++ m)) (parseInt \"nope\" >>= (\\v -> return (show v)))")))
+  (list "IO" "caught: unknown: nope"))
--- a/lib/haskell/tests/program-uniquewords.sx
+++ b/lib/haskell/tests/program-uniquewords.sx
@@ -0,0 +1,35 @@
+;; uniquewords.hs — count unique words using Data.Set.
+;;
+;; Exercises Phase 12: `import qualified Data.Set as Set`, `Set.empty`,
+;; `Set.insert`, `Set.size`, `foldl`.
+
+(define
+  hk-uniquewords-source
+  "import qualified Data.Set as Set\n\naddWord s w = Set.insert w s\n\nuniqueWords ws = foldl addWord Set.empty ws\n\nresult = uniqueWords [\"the\", \"cat\", \"the\", \"dog\", \"the\", \"cat\"]\n")
+
+(hk-test
+  "uniquewords.hs — unique count = 3"
+  (hk-deep-force
+    (hk-run (str hk-uniquewords-source "main = Set.size result\n")))
+  3)
+
+(hk-test
+  "uniquewords.hs — \"the\" present"
+  (hk-deep-force
+    (hk-run (str hk-uniquewords-source "main = Set.member \"the\" result\n")))
+  (list "True"))
+
+(hk-test
+  "uniquewords.hs — \"missing\" absent"
+  (hk-deep-force
+    (hk-run (str hk-uniquewords-source "main = Set.member \"missing\" result\n")))
+  (list "False"))
+
+(hk-test
+  "uniquewords.hs — empty list yields empty set"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.Set as Set\nmain = Set.size (foldl (\\s w -> Set.insert w s) Set.empty [])"))
+  0)
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/program-wordfreq.sx
+++ b/lib/haskell/tests/program-wordfreq.sx
@@ -0,0 +1,54 @@
+;; wordfreq.hs — word-frequency histogram using Data.Map.
+;; Source: Rosetta Code "Word frequency" (Haskell entry, simplified).
+;;
+;; Exercises Phase 11: `import qualified Data.Map as Map`, `Map.empty`,
+;; `Map.insertWith`, `Map.lookup`, `Map.findWithDefault`, `foldl`.
+
+(define
+  hk-wordfreq-source
+  "import qualified Data.Map as Map\n\ncountWord m w = Map.insertWith (+) w 1 m\n\nwordFreq xs = foldl countWord Map.empty xs\n\nresult = wordFreq [\"the\", \"cat\", \"the\", \"dog\", \"the\", \"cat\"]\n")
+
+(hk-test
+  "wordfreq.hs — \"the\" counted 3 times"
+  (hk-deep-force
+    (hk-run (str hk-wordfreq-source "main = Map.lookup \"the\" result\n")))
+  (list "Just" 3))
+
+(hk-test
+  "wordfreq.hs — \"cat\" counted 2 times"
+  (hk-deep-force
+    (hk-run (str hk-wordfreq-source "main = Map.lookup \"cat\" result\n")))
+  (list "Just" 2))
+
+(hk-test
+  "wordfreq.hs — \"dog\" counted 1 time"
+  (hk-deep-force
+    (hk-run (str hk-wordfreq-source "main = Map.lookup \"dog\" result\n")))
+  (list "Just" 1))
+
+(hk-test
+  "wordfreq.hs — \"missing\" not present"
+  (hk-deep-force
+    (hk-run (str hk-wordfreq-source "main = Map.lookup \"missing\" result\n")))
+  (list "Nothing"))
+
+(hk-test
+  "wordfreq.hs — Map.size = 3 unique words"
+  (hk-deep-force (hk-run (str hk-wordfreq-source "main = Map.size result\n")))
+  3)
+
+(hk-test
+  "wordfreq.hs — findWithDefault for missing returns 0"
+  (hk-deep-force
+    (hk-run
+      (str hk-wordfreq-source "main = Map.findWithDefault 0 \"absent\" result\n")))
+  0)
+
+(hk-test
+  "wordfreq.hs — findWithDefault for present returns count"
+  (hk-deep-force
+    (hk-run
+      (str hk-wordfreq-source "main = Map.findWithDefault 0 \"the\" result\n")))
+  3)
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/records.sx
+++ b/lib/haskell/tests/records.sx
@@ -0,0 +1,127 @@
+;; records.sx — Phase 14 record syntax tests.
+
+(define
+  hk-person-source
+  "data Person = Person { name :: String, age :: Int }\n")
+
+(define hk-pt-source "data Pt = Pt { x :: Int, y :: Int }\n")
+
+;; ── Creation ────────────────────────────────────────────────
+(hk-test
+  "creation: Person { name = \"a\", age = 1 } via accessor name"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-person-source
+        "main = name (Person { name = \"alice\", age = 30 })")))
+  "alice")
+
+(hk-test
+  "creation: source order doesn't matter (age first)"
+  (hk-deep-force
+    (hk-run
+      (str hk-person-source "main = name (Person { age = 99, name = \"bob\" })")))
+  "bob")
+
+(hk-test
+  "creation: age accessor returns the right field"
+  (hk-deep-force
+    (hk-run
+      (str hk-person-source "main = age (Person { age = 99, name = \"bob\" })")))
+  99)
+
+;; ── Accessors ──────────────────────────────────────────────
+(hk-test
+  "accessor: x of Pt"
+  (hk-deep-force
+    (hk-run (str hk-pt-source "main = x (Pt { x = 7, y = 99 })")))
+  7)
+
+(hk-test
+  "accessor: y of Pt"
+  (hk-deep-force
+    (hk-run (str hk-pt-source "main = y (Pt { x = 7, y = 99 })")))
+  99)
+
+;; ── Update — single field ──────────────────────────────────
+(hk-test
+  "update one field: age changes"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-person-source
+        "alice = Person { name = \"alice\", age = 30 }\nmain = age (alice { age = 31 })")))
+  31)
+
+(hk-test
+  "update one field: name preserved"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-person-source
+        "alice = Person { name = \"alice\", age = 30 }\nmain = name (alice { age = 31 })")))
+  "alice")
+
+;; ── Update — two fields ────────────────────────────────────
+(hk-test
+  "update two fields: both changed"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-person-source
+        "alice = Person { name = \"alice\", age = 30 }\nbob = alice { name = \"bob\", age = 50 }\nmain = age bob")))
+  50)
+
+(hk-test
+  "update two fields: name takes new value"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-person-source
+        "alice = Person { name = \"alice\", age = 30 }\nbob = alice { name = \"bob\", age = 50 }\nmain = name bob")))
+  "bob")
+
+;; ── Record patterns ────────────────────────────────────────
+(hk-test
+  "case-alt record pattern: Pt { x = a }"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-pt-source
+        "getX p = case p of Pt { x = a } -> a\nmain = getX (Pt { x = 7, y = 99 })")))
+  7)
+
+(hk-test
+  "case-alt record pattern: multi-field bind"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-pt-source
+        "sumPt p = case p of Pt { x = a, y = b } -> a + b\nmain = sumPt (Pt { x = 3, y = 4 })")))
+  7)
+
+(hk-test
+  "fun-LHS record pattern"
+  (hk-deep-force
+    (hk-run
+      (str
+        hk-person-source
+        "getName (Person { name = n }) = n\nmain = getName (Person { name = \"alice\", age = 30 })")))
+  "alice")
+
+;; ── deriving Show on a record ───────────────────────────────
+(hk-test
+  "deriving Show on a record produces positional output"
+  (hk-deep-force
+    (hk-run
+      "data Person = Person { name :: String, age :: Int } deriving (Show)\nmain = show (Person { name = \"alice\", age = 30 })"))
+  "Person \"alice\" 30")
+
+(hk-test
+  "deriving Show on Pt"
+  (hk-deep-force
+    (hk-run
+      "data Pt = Pt { x :: Int, y :: Int } deriving (Show)\nmain = show (Pt { x = 3, y = 4 })"))
+  "Pt 3 4")
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/set.sx
+++ b/lib/haskell/tests/set.sx
@@ -0,0 +1,119 @@
+;; set.sx — Phase 12 Data.Set unit tests.
+
+;; ── SX-level (direct hk-set-*) ───────────────────────────────
+(hk-test
+  "hk-set-empty: size 0 + null"
+  (list (hk-set-size hk-set-empty) (hk-set-null hk-set-empty))
+  (list 0 true))
+
+(hk-test
+  "hk-set-singleton: member yes"
+  (let
+    ((s (hk-set-singleton 5)))
+    (list (hk-set-size s) (hk-set-member 5 s) (hk-set-member 99 s)))
+  (list 1 true false))
+
+(hk-test
+  "hk-set-insert: idempotent"
+  (let
+    ((s (hk-set-insert 1 (hk-set-insert 1 hk-set-empty))))
+    (hk-set-size s))
+  1)
+
+(hk-test
+  "hk-set-from-list: dedupes"
+  (hk-set-to-asc-list (hk-set-from-list (list 3 1 4 1 5 9 2 6)))
+  (list 1 2 3 4 5 6 9))
+
+(hk-test
+  "hk-set-delete: removes"
+  (let
+    ((s (hk-set-from-list (list 1 2 3))))
+    (hk-set-to-asc-list (hk-set-delete 2 s)))
+  (list 1 3))
+
+(hk-test
+  "hk-set-union"
+  (hk-set-to-asc-list
+    (hk-set-union
+      (hk-set-from-list (list 1 2 3))
+      (hk-set-from-list (list 3 4 5))))
+  (list 1 2 3 4 5))
+
+(hk-test
+  "hk-set-intersection"
+  (hk-set-to-asc-list
+    (hk-set-intersection
+      (hk-set-from-list (list 1 2 3 4))
+      (hk-set-from-list (list 3 4 5 6))))
+  (list 3 4))
+
+(hk-test
+  "hk-set-difference"
+  (hk-set-to-asc-list
+    (hk-set-difference
+      (hk-set-from-list (list 1 2 3 4))
+      (hk-set-from-list (list 3 4 5))))
+  (list 1 2))
+
+(hk-test
+  "hk-set-is-subset-of: yes"
+  (hk-set-is-subset-of
+    (hk-set-from-list (list 2 3))
+    (hk-set-from-list (list 1 2 3 4)))
+  true)
+
+(hk-test
+  "hk-set-is-subset-of: no"
+  (hk-set-is-subset-of
+    (hk-set-from-list (list 5 6))
+    (hk-set-from-list (list 1 2 3 4)))
+  false)
+
+(hk-test
+  "hk-set-filter"
+  (hk-set-to-asc-list
+    (hk-set-filter (fn (k) (> k 2)) (hk-set-from-list (list 1 2 3 4 5))))
+  (list 3 4 5))
+
+(hk-test
+  "hk-set-map"
+  (hk-set-to-asc-list
+    (hk-set-map (fn (k) (* k 10)) (hk-set-from-list (list 1 2 3))))
+  (list 10 20 30))
+
+(hk-test
+  "hk-set-foldr: sum"
+  (hk-set-foldr + 0 (hk-set-from-list (list 1 2 3 4 5)))
+  15)
+
+;; ── Haskell-level (Set.* via import wiring) ──────────────────
+(hk-test
+  "Set.size after Set.insert chain"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.Set as Set\nmain = Set.size (Set.insert 3 (Set.insert 1 (Set.insert 2 Set.empty)))"))
+  3)
+
+(hk-test
+  "Set.member true"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.Set as Set\nmain = Set.member 5 (Set.insert 5 Set.empty)"))
+  (list "True"))
+
+(hk-test
+  "Set.union via Haskell"
+  (hk-deep-force
+    (hk-run
+      "import Data.Set\nmain = Set.size (Set.union (Set.insert 1 Set.empty) (Set.insert 2 Set.empty))"))
+  2)
+
+(hk-test
+  "Set.isSubsetOf via Haskell"
+  (hk-deep-force
+    (hk-run
+      "import qualified Data.Set as S\nmain = S.isSubsetOf (S.insert 1 S.empty) (S.insert 2 (S.insert 1 S.empty))"))
+  (list "True"))
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/show.sx
+++ b/lib/haskell/tests/show.sx
@@ -0,0 +1,140 @@
+;; show.sx — tests for the Show / Read class plumbing.
+;;
+;; Covers Phase 8:
+;;  - showsPrec / showParen / shows / showString stubs
+;;  - Read class stubs (reads / readsPrec / read)
+;;  - direct show coverage (Int, Bool, String, list, tuple, Maybe, ADT, ...)
+
+;; ── ShowS / showsPrec / showParen stubs ──────────────────────
+(hk-test
+  "shows: prepends show output"
+  (hk-deep-force (hk-run "main = shows 5 \"abc\""))
+  "5abc")
+
+(hk-test
+  "shows: works on True"
+  (hk-deep-force (hk-run "main = shows True \"x\""))
+  "Truex")
+
+(hk-test
+  "showString: prepends literal"
+  (hk-deep-force (hk-run "main = showString \"hello\" \" world\""))
+  "hello world")
+
+(hk-test
+  "showParen True: wraps inner output in parens"
+  (hk-deep-force (hk-run "main = showParen True (showString \"inside\") \"\""))
+  "(inside)")
+
+(hk-test
+  "showParen False: passes through unchanged"
+  (hk-deep-force (hk-run "main = showParen False (showString \"inside\") \"\""))
+  "inside")
+
+(hk-test
+  "showsPrec: prepends show output regardless of prec"
+  (hk-deep-force (hk-run "main = showsPrec 11 42 \"end\""))
+  "42end")
+
+(hk-test
+  "showParen + manual composition: build (Just 3)"
+  (hk-deep-force
+    (hk-run
+      "buildJust3 s = showString \"Just \" (shows 3 s)\nmain = showParen True buildJust3 \"\""))
+  "(Just 3)")
+
+;; ── Read stubs ───────────────────────────────────────────────
+(hk-test
+  "reads: stub returns empty list (null-check)"
+  (hk-deep-force (hk-run "main = show (null (reads \"42\"))"))
+  "True")
+
+(hk-test
+  "readsPrec: stub returns empty list"
+  (hk-deep-force (hk-run "main = show (null (readsPrec 0 \"True\"))"))
+  "True")
+
+(hk-test
+  "reads: type-checks in expression context (length)"
+  (hk-deep-force (hk-run "main = show (length (reads \"abc\"))"))
+  "0")
+
+;; ── Direct `show` audit coverage ─────────────────────────────
+(hk-test "show Int" (hk-deep-force (hk-run "main = show 42")) "42")
+
+(hk-test
+  "show negative Int"
+  (hk-deep-force (hk-run "main = show (negate 5)"))
+  "-5")
+
+(hk-test "show Bool True" (hk-deep-force (hk-run "main = show True")) "True")
+
+(hk-test
+  "show Bool False"
+  (hk-deep-force (hk-run "main = show False"))
+  "False")
+
+(hk-test
+  "show String quotes the value"
+  (hk-deep-force (hk-run "main = show \"hello\""))
+  "\"hello\"")
+
+(hk-test
+  "show list of Int"
+  (hk-deep-force (hk-run "main = show [1,2,3]"))
+  "[1,2,3]")
+
+(hk-test
+  "show empty list"
+  (hk-deep-force (hk-run "main = show (drop 5 [1,2,3])"))
+  "[]")
+
+(hk-test
+  "show pair tuple"
+  (hk-deep-force (hk-run "main = show (1, True)"))
+  "(1,True)")
+
+(hk-test
+  "show triple tuple"
+  (hk-deep-force (hk-run "main = show (1, 2, 3)"))
+  "(1,2,3)")
+
+(hk-test
+  "show Maybe Nothing"
+  (hk-deep-force (hk-run "main = show Nothing"))
+  "Nothing")
+
+(hk-test
+  "show Maybe Just"
+  (hk-deep-force (hk-run "main = show (Just 3)"))
+  "Just 3")
+
+(hk-test
+  "show nested Just wraps inner in parens"
+  (hk-deep-force (hk-run "main = show (Just (Just 3))"))
+  "Just (Just 3)")
+
+(hk-test
+  "show Just (negate 3) wraps negative in parens"
+  (hk-deep-force (hk-run "main = show (Just (negate 3))"))
+  "Just (-3)")
+
+(hk-test
+  "show custom nullary ADT"
+  (hk-deep-force
+    (hk-run "data Day = Mon | Tue | Wed deriving (Show)\nmain = show Tue"))
+  "Tue")
+
+(hk-test
+  "show custom multi-constructor ADT"
+  (hk-deep-force
+    (hk-run
+      "data Shape = Pt | Sq Int | Rect Int Int deriving (Show)\nmain = show (Rect 3 4)"))
+  "Rect 3 4")
+
+(hk-test
+  "show list of Maybe wraps each element"
+  (hk-deep-force (hk-run "main = show [Just 1, Nothing, Just 2]"))
+  "[Just 1,Nothing,Just 2]")
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/lib/haskell/tests/stdlib.sx
+++ b/lib/haskell/tests/stdlib.sx
@@ -37,11 +37,11 @@
 (hk-ts "show neg" "negate 7" "-7")
 (hk-ts "show bool T" "True" "True")
 (hk-ts "show bool F" "False" "False")
-(hk-ts "show list" "[1,2,3]" "[1, 2, 3]")
-(hk-ts "show Just" "Just 5" "(Just 5)")
+(hk-ts "show list" "[1,2,3]" "[1,2,3]")
+(hk-ts "show Just" "Just 5" "Just 5")
 (hk-ts "show Nothing" "Nothing" "Nothing")
 (hk-ts "show LT" "LT" "LT")
-(hk-ts "show tuple" "(1, True)" "(1, True)")
+(hk-ts "show tuple" "(1, True)" "(1,True)")

 ;; ── Num extras ───────────────────────────────────────────────
 (hk-test "signum pos" (hk-deep-force (hk-run "main = signum 5")) 1)
@@ -59,13 +59,13 @@
 (hk-test
  "foldr cons"
  (hk-deep-force (hk-run "main = show (foldr (:) [] [1,2,3])"))
-  "[1, 2, 3]")
+  "[1,2,3]")

 ;; ── List ops ─────────────────────────────────────────────────
 (hk-test
  "reverse"
  (hk-deep-force (hk-run "main = show (reverse [1,2,3])"))
-  "[3, 2, 1]")
+  "[3,2,1]")
 (hk-test "null []" (hk-deep-force (hk-run "main = null []")) (list "True"))
 (hk-test
  "null xs"
@@ -82,7 +82,7 @@
 (hk-test
  "zip"
  (hk-deep-force (hk-run "main = show (zip [1,2] [3,4])"))
-  "[(1, 3), (2, 4)]")
+  "[(1,3),(2,4)]")
 (hk-test "sum" (hk-deep-force (hk-run "main = sum [1,2,3,4,5]")) 15)
 (hk-test "product" (hk-deep-force (hk-run "main = product [1,2,3,4]")) 24)
 (hk-test "maximum" (hk-deep-force (hk-run "main = maximum [3,1,9,2]")) 9)
@@ -112,7 +112,7 @@
 (hk-test
  "fmap list"
  (hk-deep-force (hk-run "main = show (fmap (+1) [1,2,3])"))
-  "[2, 3, 4]")
+  "[2,3,4]")

 ;; ── Monad / Applicative ──────────────────────────────────────
 (hk-test "return" (hk-deep-force (hk-run "main = return 7")) (list "IO" 7))
@@ -134,7 +134,7 @@
 (hk-test
  "lookup hit"
  (hk-deep-force (hk-run "main = show (lookup 2 [(1,10),(2,20)])"))
-  "(Just 20)")
+  "Just 20")
 (hk-test
  "lookup miss"
  (hk-deep-force (hk-run "main = show (lookup 9 [(1,10)])"))
--- a/lib/haskell/tests/string-char.sx
+++ b/lib/haskell/tests/string-char.sx
@@ -0,0 +1,139 @@
+;; String / Char tests — Phase 7 items 1-4.
+;;
+;; Covers:
+;;   hk-str? / hk-str-head / hk-str-tail / hk-str-null?   (runtime helpers)
+;;   chr / ord / toUpper / toLower                          (builtins in eval)
+;;   cons-pattern on strings via match.sx                   (":"-intercept)
+;;   empty-list pattern on strings via match.sx             ("[]"-intercept)
+
+;; ── hk-str? predicate ────────────────────────────────────────────────────
+(hk-test "hk-str? native string" (hk-str? "hello") true)
+
+(hk-test "hk-str? empty string" (hk-str? "") true)
+
+(hk-test "hk-str? view dict" (hk-str? {:hk-off 1 :hk-str "hi"}) true)
+
+(hk-test "hk-str? rejects number" (hk-str? 42) false)
+
+;; ── hk-str-null? predicate ───────────────────────────────────────────────
+(hk-test "hk-str-null? empty string" (hk-str-null? "") true)
+
+(hk-test "hk-str-null? non-empty" (hk-str-null? "a") false)
+
+(hk-test "hk-str-null? exhausted view" (hk-str-null? {:hk-off 2 :hk-str "hi"}) true)
+
+(hk-test "hk-str-null? live view" (hk-str-null? {:hk-off 1 :hk-str "hi"}) false)
+
+;; ── hk-str-head ──────────────────────────────────────────────────────────
+(hk-test "hk-str-head native string" (hk-str-head "hello") 104)
+
+(hk-test "hk-str-head view at offset" (hk-str-head {:hk-off 1 :hk-str "hello"}) 101)
+
+;; ── hk-str-tail ──────────────────────────────────────────────────────────
+(hk-test "hk-str-tail of single char is nil" (hk-str-tail "h") (list "[]"))
+
+(hk-test
+  "hk-str-tail of two-char string is live view"
+  (hk-str-null? (hk-str-tail "hi"))
+  false)
+
+(hk-test
+  "hk-str-tail head of tail of hi is i"
+  (hk-str-head (hk-str-tail "hi"))
+  105)
+
+;; ── chr / ord ────────────────────────────────────────────────────────────
+(hk-test "chr 65 = A" (hk-eval-expr-source "chr 65") "A")
+
+(hk-test "chr 104 = h" (hk-eval-expr-source "chr 104") "h")
+
+(hk-test "ord char literal 'A' = 65" (hk-eval-expr-source "ord 'A'") 65)
+
+(hk-test "ord char literal 'a' = 97" (hk-eval-expr-source "ord 'a'") 97)
+
+(hk-test
+  "ord of head string = char code"
+  (hk-eval-expr-source "ord (head \"hello\")")
+  104)
+
+;; ── toUpper / toLower ────────────────────────────────────────────────────
+(hk-test "toUpper 97 = 65 (a->A)" (hk-eval-expr-source "toUpper 97") 65)
+
+(hk-test
+  "toUpper 65 = 65 (already upper)"
+  (hk-eval-expr-source "toUpper 65")
+  65)
+
+(hk-test
+  "toUpper 48 = 48 (digit unchanged)"
+  (hk-eval-expr-source "toUpper 48")
+  48)
+
+(hk-test "toLower 65 = 97 (A->a)" (hk-eval-expr-source "toLower 65") 97)
+
+(hk-test
+  "toLower 97 = 97 (already lower)"
+  (hk-eval-expr-source "toLower 97")
+  97)
+
+(hk-test
+  "toLower 48 = 48 (digit unchanged)"
+  (hk-eval-expr-source "toLower 48")
+  48)
+
+;; ── Pattern matching on strings ──────────────────────────────────────────
+(hk-test
+  "cons pattern: head of hello = 104"
+  (hk-eval-expr-source "case \"hello\" of { (x:_) -> x }")
+  104)
+
+(hk-test
+  "cons pattern: tail is traversable"
+  (hk-eval-expr-source "case \"hi\" of { (_:xs) -> case xs of { (y:_) -> y } }")
+  105)
+
+(hk-test
+  "empty list pattern matches empty string"
+  (hk-eval-expr-source "case \"\" of { [] -> True; _ -> False }")
+  (list "True"))
+
+(hk-test
+  "empty list pattern fails on non-empty"
+  (hk-eval-expr-source "case \"a\" of { [] -> True; _ -> False }")
+  (list "False"))
+
+(hk-test
+  "cons pattern fails on empty string"
+  (hk-eval-expr-source "case \"\" of { (_:_) -> True; _ -> False }")
+  (list "False"))
+
+;; ── Haskell programs using string traversal ──────────────────────────────
+(hk-test
+  "null prelude on empty string"
+  (hk-eval-expr-source "null \"\"")
+  (list "True"))
+
+(hk-test
+  "null prelude on non-empty string"
+  (hk-eval-expr-source "null \"abc\"")
+  (list "False"))
+
+(hk-test
+  "length of string via cons recursion"
+  (hk-eval-expr-source "let { f [] = 0; f (_:xs) = 1 + f xs } in f \"hello\"")
+  5)
+
+(hk-test
+  "map ord over string gives char codes"
+  (hk-deep-force (hk-eval-expr-source "map ord \"abc\""))
+  (list ":" 97 (list ":" 98 (list ":" 99 (list "[]")))))
+
+(hk-test
+  "map toUpper over char codes then chr"
+  (hk-eval-expr-source "chr (toUpper (ord (head \"abc\")))")
+  "A")
+
+(hk-test
+  "head then ord using prelude head"
+  (hk-eval-expr-source "ord (head \"hello\")")
+  104)
--- a/lib/haskell/tests/typecheck.sx
+++ b/lib/haskell/tests/typecheck.sx
@@ -16,15 +16,18 @@
      true)))

 ;; ─── Valid programs pass through ─────────────────────────────────────────────
-(hk-test "typed ok: simple arithmetic" (hk-run-typed "main = 1 + 2") 3)
+(hk-test "typed ok: simple arithmetic"
+  (hk-deep-force (hk-run-typed "main = 1 + 2")) 3)

-(hk-test "typed ok: boolean" (hk-run-typed "main = True") (list "True"))
+(hk-test "typed ok: boolean"
+  (hk-deep-force (hk-run-typed "main = True")) (list "True"))

-(hk-test "typed ok: let binding" (hk-run-typed "main = let x = 1 in x + 2") 3)
+(hk-test "typed ok: let binding"
+  (hk-deep-force (hk-run-typed "main = let x = 1 in x + 2")) 3)

 (hk-test
  "typed ok: two independent fns"
-  (hk-run-typed "f x = x + 1\nmain = f 5")
+  (hk-deep-force (hk-run-typed "f x = x + 1\nmain = f 5"))
  6)

 ;; ─── Untypeable programs are rejected ────────────────────────────────────────
@@ -76,7 +79,7 @@

 (hk-test
  "run-typed sig ok: Int declared matches"
-  (hk-run-typed "main :: Int\nmain = 1 + 2")
+  (hk-deep-force (hk-run-typed "main :: Int\nmain = 1 + 2"))
  3)

 {:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}
--- a/plans/apl-on-sx.md
+++ b/plans/apl-on-sx.md
@@ -135,6 +135,48 @@ and tightens loose ends.
  on error switches to the trap branch.  Define `apl-throw` and a small
  set of error codes; use `try`/`catch` from the host.

+### Phase 8 — fill the gaps left after end-to-end
+
+Phase 7 wired the stack together; Phase 8 closes deferred items, lets real
+programs run from source, and starts pushing on performance.
+
+- [x] **Quick-wins bundle** (one iteration) — three small fixes that each unblock
+  real programs:
+  - decimal literals: `read-digits!` consumes one trailing `.` plus more digits
+    so `3.7` tokenises as one number;
+  - `⎕←` (print) — tokenizer special-case: when `⎕` is followed by `←`, emit
+    a single `:name "⎕←"` token (don't split on the assign glyph);
+  - string values in `apl-eval-ast` — handle `:str` (parser already produces
+    them) by wrapping into a vector of character codes (or rank-0 string).
+- [x] **Named function definitions** — `f ← {⍺+⍵} ⋄ 1 f 2` and `2 f 3`.
+  - parser: when `:assign`'s RHS is a `:dfn`, mark it as a function binding;
+  - eval-ast: `:assign` of a dfn stores the dfn in env;
+  - parser: a name in fn-position whose env value is a dfn dispatches as a fn;
+  - resolver: extend `apl-resolve-monadic`/`-dyadic` with a `:fn-name` case
+    that calls `apl-call-dfn`/`apl-call-dfn-m`.
+- [x] **Multi-axis bracket indexing** — `A[I;J]` and `A[;J]` and `A[I;]`.
+  - parser: split bracket content on `:semi` at depth 0; emit
+    `(:dyad ⌷ (:vec I J) A)`;
+  - runtime: extend `apl-squad` to accept a vector of indices, treating
+    `nil` / empty axis as "all";
+  - 5+ tests across vector and matrix.
+- [x] **`.apl` files as actual tests** — `lib/apl/tests/programs/*.apl` are
+  currently documentation. Add `apl-run-file path → array` plus tests that
+  load each file, execute it, and assert the expected result. Makes the
+  classic-program corpus self-validating instead of two parallel impls.
+  _(Embedded source-string approach: tests/programs-e2e.sx runs the same
+  algorithms as the .apl docs through the full pipeline. The original
+  one-liners (e.g. primes' inline `⍵←⍳⍵`) need parser features
+  (compress-as-fn, inline assign) we haven't built yet — multi-stmt forms
+  used instead. Slurp/read-file primitive missing in OCaml SX runtime.)_
+- [x] **Train/fork notation** — `(f g h) ⍵ ↔ (f ⍵) g (h ⍵)` (3-train);
+  `(g h) ⍵ ↔ g (h ⍵)` (2-train atop). Parser: detect when a parenthesised
+  subexpression is all functions and emit `(:train fns)`; resolver: build the
+  derived function; tests for mean-via-train (`+/÷≢`).
+- [x] **Performance pass** — n-queens(8) currently ~30 s/iter (tight on the
+  300 s timeout). Target: profile the inner loop, eliminate quadratic
+  list-append, restore the `queens(8)` test.
+
 ## SX primitive baseline

 Use vectors for arrays; numeric tower + rationals for numbers; ADTs for tagged data;
@@ -149,6 +191,13 @@ data; format for string templating.

 _Newest first._

+- 2026-05-07: Phase 8 step 6 — perf: swapped (append acc xs) → (append xs acc) in apl-permutations to make permutation generation linear instead of quadratic; q(7) 32s→12s; q(8)=92 test restored within 300s timeout; **Phase 8 complete, all unchecked items ticked**; 497/497
+- 2026-05-07: Phase 8 step 5 — train/fork notation. Parser :lparen detects all-fn inner segments → emits :train AST; resolver covers 2-atop & 3-fork for both monadic and dyadic. `(+/÷≢) 1..5 → 3` (mean), `(- ⌊) 5 → -5` (atop), `2(+×-)5 → -21` (dyadic fork), `(⌈/-⌊/) → 8` (range); +6 tests; 496/496
+- 2026-05-07: Phase 8 step 4 — programs-e2e.sx runs classic-algorithm shapes through full pipeline (factorial via ∇, triangulars, sum-of-squares, divisor-counts, prime-mask, named-fn composition, dyadic max-of-two, Newton step); also added ⌿ + ⍀ to glyph sets (were silently skipped); +15 tests; 490/490
+- 2026-05-07: Phase 8 step 3 — multi-axis bracket A[I;J] / A[I;] / A[;J] via :bracket AST + apl-bracket-multi runtime; split-bracket-content scans :semi at depth 0; apl-cartesian builds index combinations; nil axis = "all"; scalar axis collapses; +8 tests; 475/475
+- 2026-05-07: Phase 8 step 2 — named function defs end-to-end via parser pre-scan; apl-known-fn-names + apl-collect-fn-bindings detect `name ← {...}` patterns; collect-segments-loop emits :fn-name for known names; resolver looks up env for :fn-name; supports recursion (∇ in named dfn); +7 tests including fact via ∇; 467/467
+- 2026-05-07: Phase 8 step 1 — quick-wins bundle: decimal literals (3.7, ¯2.5), ⎕← passthrough as monadic fn (single-token via tokenizer special-case), :str AST in eval-ast (single-char→scalar, multi-char→vec); +10 tests; 460/460
+- 2026-05-07: Phase 8 added — quick-wins bundle (decimals + ⎕← + strings), named functions, multi-axis bracket, .apl-files-as-tests, trains, perf
 - 2026-05-07: Phase 7 step 6 — :Trap exception machinery via R7RS guard; apl-throw raises tagged error, apl-trap-matches? checks codes (0=catch-all), :trap clause in apl-tradfn-eval-stmt wraps try-block with guard; :throw AST for testing; **Phase 7 complete, all unchecked plan items done**; +5 tests; 450/450
 - 2026-05-07: Phase 7 step 5 — idiom corpus 34→64 (+30 source-string idioms via apl-run); also fixed tokenizer + parser to recognize ≢ and ≡ glyphs (were silently skipped); 445/445
 - 2026-05-07: Phase 7 step 4 — bracket indexing `A[I]` desugared to `(:dyad ⌷ I A)` via maybe-bracket helper, wired into :name + :lparen branches of collect-segments-loop; multi-axis (A[I;J]) deferred (semicolon split); +7 tests; 415/415
--- a/plans/haskell-completeness.md
+++ b/plans/haskell-completeness.md
@@ -75,21 +75,21 @@ No OCaml changes are needed. The view type is fully representable as an SX dict.

 ### Phase 7 — String = [Char] (performant string views)

- [ ] Add `hk-str?` predicate to `runtime.sx` covering both native SX strings
+- [x] Add `hk-str?` predicate to `runtime.sx` covering both native SX strings
  and `{:hk-str buf :hk-off n}` view dicts.
- [ ] Implement `hk-str-head`, `hk-str-tail`, `hk-str-null?` helpers in
+- [x] Implement `hk-str-head`, `hk-str-tail`, `hk-str-null?` helpers in
  `runtime.sx`.
- [ ] In `match.sx`, intercept cons-pattern `":"` when scrutinee satisfies
+- [x] In `match.sx`, intercept cons-pattern `":"` when scrutinee satisfies
  `hk-str?`; decompose to (char-int, view) instead of the tagged-list path.
  Nil-pattern `"[]"` matches `hk-str-null?`.
- [ ] Add builtins: `chr` (int → single-char string), verify `ord` returns int,
+- [x] Add builtins: `chr` (int → single-char string), verify `ord` returns int,
  `toUpper`, `toLower` (ASCII range arithmetic on ints).
- [ ] Ensure `++` between two strings concatenates natively via `str` rather
+- [x] Ensure `++` between two strings concatenates natively via `str` rather
  than building a cons spine.
- [ ] Tests in `lib/haskell/tests/string-char.sx` (≥ 15 tests: head/tail on
+- [x] Tests in `lib/haskell/tests/string-char.sx` (≥ 15 tests: head/tail on
  string literal, map over string, filter chars, chr/ord roundtrip, toUpper,
  toLower, null/empty string view).
- [ ] Conformance programs (WebFetch + adapt):
+- [x] Conformance programs (WebFetch + adapt):
  - `caesar.hs` — Caesar cipher. Exercises `map`, `chr`, `ord`, `toUpper`,
    `toLower` on characters.
  - `runlength-str.hs` — run-length encoding on a String. Exercises string
@@ -97,61 +97,81 @@ No OCaml changes are needed. The view type is fully representable as an SX dict.

 ### Phase 8 — `show` for arbitrary types

- [ ] Audit `hk-show-val` in `runtime.sx` — ensure output format matches
-  Haskell 98: `"Just 3"`, `"[1,2,3]"`, `"(True,False)"`, `"'a'"` (Char shows
-  with single-quotes), `"\"hello\""` (String shows with escaped double-quotes).
- [ ] `show` Prelude binding calls `hk-show-val`; `print x = putStrLn (show x)`.
- [ ] `deriving Show` auto-generates proper show for record-style and
+- [x] Audit `hk-show-val` in `runtime.sx` — ensure output format matches
+  Haskell 98: `"Just 3"`, `"[1,2,3]"`, `"(True,False)"`, `"\"hello\""` (String
+  shows with escaped double-quotes). _Deferred:_ `"'a'"` Char single-quotes
+  (needs Char tagging — currently Char = Int by representation, ambiguous in
+  show); `\n`/`\t` escape inside Strings.
+- [x] `show` Prelude binding calls `hk-show-val`; `print x = putStrLn (show x)`.
+- [x] `deriving Show` auto-generates proper show for record-style and
  multi-constructor ADTs. Nested application arguments wrapped in parens:
-  if `show arg` contains a space, emit `"(" ++ show arg ++ ")"`.
- [ ] `showsPrec` / `showParen` stubs so hand-written Show instances compile.
- [ ] `Read` class stub — just enough for `reads :: String -> [(a,String)]` to
+  if `show arg` contains a space, emit `"(" ++ show arg ++ ")"`. _Records
+  deferred — Phase 14._
+- [x] `showsPrec` / `showParen` stubs so hand-written Show instances compile.
+- [x] `Read` class stub — just enough for `reads :: String -> [(a,String)]` to
  type-check; no real parser needed yet.
- [ ] Tests in `lib/haskell/tests/show.sx` (≥ 12 tests: show Int, show Bool,
+- [x] Tests in `lib/haskell/tests/show.sx` (≥ 12 tests: show Int, show Bool,
  show Char, show String, show list, show tuple, show Maybe, show custom ADT,
  deriving Show on multi-constructor type, nested constructor parens).
- [ ] Conformance programs:
+  _Char tests deferred: Char = Int representation; show on a Char is currently
+  `"97"` not `"'a'"`._
+- [x] Conformance programs:
  - `showadt.hs` — `data Expr = Lit Int | Add Expr Expr | Mul Expr Expr`
    with `deriving Show`; prints a tree.
  - `showio.hs` — `print` on various types in a `do` block.

 ### Phase 9 — `error` / `undefined`

- [ ] `error :: String -> a` — raises `(raise (list "hk-error" msg))` in SX.
- [ ] `undefined :: a` = `error "Prelude.undefined"`.
- [ ] Partial functions emit proper error messages: `head []` →
+- [x] `error :: String -> a` — raises `(raise "hk-error: <msg>")` in SX.
+  _Plan amended:_ SX's `apply` rewrites unhandled list raises to a string
+  `"Unhandled exception: <serialized>"` before any user handler sees them, so
+  the tag has to live in a string prefix rather than as the head of a list.
+  Catchers use `(index-of e "hk-error: ")` to detect.
+- [x] `undefined :: a` = `error "Prelude.undefined"`.
+- [x] Partial functions emit proper error messages: `head []` →
  `"Prelude.head: empty list"`, `tail []` → `"Prelude.tail: empty list"`,
  `fromJust Nothing` → `"Maybe.fromJust: Nothing"`.
- [ ] Top-level `hk-run-io` catches `hk-error` tag and returns it as a tagged
+- [x] Top-level `hk-run-io` catches `hk-error` tag and returns it as a tagged
  error result so test suites can inspect it without crashing.
- [ ] `hk-test-error` helper in `testlib.sx`:
+- [x] `hk-test-error` helper in `testlib.sx`:
  `(hk-test-error "desc" thunk expected-substring)` — asserts the thunk raises
  an `hk-error` whose message contains the given substring.
- [ ] Tests in `lib/haskell/tests/errors.sx` (≥ 10 tests: error message
+- [x] Tests in `lib/haskell/tests/errors.sx` (≥ 10 tests: error message
  content, undefined, head/tail/fromJust on bad input, `hk-test-error` helper).
- [ ] Conformance programs:
+- [x] Conformance programs:
  - `partial.hs` — exercises `head []`, `tail []`, `fromJust Nothing` caught
    at the top level; shows error messages.

 ### Phase 10 — Numeric tower

- [ ] `Integer` — verify SX numbers handle large integers without overflow;
-  note limit in a comment if there is one.
- [ ] `fromIntegral :: (Integral a, Num b) => a -> b` — identity in our runtime
+- [x] `Integer` — verify SX numbers handle large integers without overflow;
+  note limit in a comment if there is one. _Verified; documented practical
+  limit of 2^53 (≈ 9e15) due to Haskell tokenizer parsing larger int literals
+  as floats. Raw SX is exact to ±2^62. See header comment in `numerics.sx`._
+- [x] `fromIntegral :: (Integral a, Num b) => a -> b` — identity in our runtime
  (all numbers share one SX type); register as a builtin no-op with the correct
-  typeclass signature.
- [ ] `toInteger`, `fromInteger` — same treatment.
- [ ] Float/Double literals round-trip through `hk-show-val`:
-  `show 3.14 = "3.14"`, `show 1.0e10 = "1.0e10"`.
- [ ] Math builtins: `sqrt`, `floor`, `ceiling`, `round`, `truncate` — call
+  typeclass signature. _Already in `hk-prelude-src` as `fromIntegral x = x`;
+  verified with new tests in `numerics.sx`._
+- [x] `toInteger`, `fromInteger` — same treatment. _Already in prelude as
+  `toInteger x = x` and `fromInteger x = x`; verified with new tests._
+- [x] Float/Double literals round-trip through `hk-show-val`:
+  `show 3.14 = "3.14"`, `show 1.0e10 = "1.0e10"`. _Partial: fractional floats
+  render correctly (`3.14`, `-3.14`, `1.0e-3`); whole-valued floats render as
+  ints (`1.0e10` → `"10000000000"`) because our system can't distinguish
+  `42` from `42.0` — both are SX numbers where `integer?` is true. Existing
+  tests like `show 42 = "42"` rely on this rendering. Documented in `numerics.sx`._
+- [x] Math builtins: `sqrt`, `floor`, `ceiling`, `round`, `truncate` — call
  the corresponding SX numeric primitives.
- [ ] `Fractional` typeclass stub: `(/)`, `recip`, `fromRational`.
- [ ] `Floating` typeclass stub: `pi`, `exp`, `log`, `sin`, `cos`, `(**)`
+- [x] `Fractional` typeclass stub: `(/)`, `recip`, `fromRational`. _(/)
+  already a binop; `recip x = 1 / x` and `fromRational x = x` registered as
+  builtins in the post-prelude block._
+- [x] `Floating` typeclass stub: `pi`, `exp`, `log`, `sin`, `cos`, `(**)`
  (power operator, maps to SX exponentiation).
- [ ] Tests in `lib/haskell/tests/numeric.sx` (≥ 15 tests: fromIntegral
-  identity, sqrt/floor/ceiling/round on known values, Float literal show,
-  division, pi, `2 ** 10 = 1024.0`).
- [ ] Conformance programs:
+- [x] Tests in `lib/haskell/tests/numerics.sx` (37/37 — well past the ≥15
+  target; covers fromIntegral identity, sqrt/floor/ceiling/round/truncate,
+  Float literal show, division/recip/fromRational, pi/exp/log/sin/cos,
+  `2 ** 10 = 1024`. Filename is plural — divergence noted in the plan.)
+- [x] Conformance programs:
  - `statistics.hs` — mean, variance, std-dev on a `[Double]`. Exercises
    `fromIntegral`, `sqrt`, `/`.
  - `newton.hs` — Newton's method for square root. Exercises `Float`, `abs`,
@@ -159,81 +179,92 @@ No OCaml changes are needed. The view type is fully representable as an SX dict.

 ### Phase 11 — Data.Map

- [ ] Implement a weight-balanced BST in pure SX in `lib/haskell/map.sx`.
+- [x] Implement a weight-balanced BST in pure SX in `lib/haskell/map.sx`.
  Internal node representation: `("Map-Node" key val left right size)`.
  Leaf: `("Map-Empty")`.
- [ ] Core operations: `empty`, `singleton`, `insert`, `lookup`, `delete`,
+- [x] Core operations: `empty`, `singleton`, `insert`, `lookup`, `delete`,
  `member`, `size`, `null`.
- [ ] Bulk operations: `fromList`, `toList`, `toAscList`, `keys`, `elems`.
- [ ] Combining: `unionWith`, `intersectionWith`, `difference`.
- [ ] Transforming: `foldlWithKey`, `foldrWithKey`, `mapWithKey`, `filterWithKey`.
- [ ] Updating: `adjust`, `insertWith`, `insertWithKey`, `alter`.
- [ ] Module wiring: `import Data.Map` and `import qualified Data.Map as Map`
+- [x] Bulk operations: `fromList`, `toList`, `toAscList`, `keys`, `elems`.
+- [x] Combining: `unionWith`, `intersectionWith`, `difference`.
+- [x] Transforming: `foldlWithKey`, `foldrWithKey`, `mapWithKey`, `filterWithKey`.
+- [x] Updating: `adjust`, `insertWith`, `insertWithKey`, `alter`.
+- [x] Module wiring: `import Data.Map` and `import qualified Data.Map as Map`
  resolve to the `map.sx` namespace dict in the eval import handler.
- [ ] Unit tests in `lib/haskell/tests/map.sx` (≥ 20 tests: empty, singleton,
-  insert + lookup hit/miss, delete root, fromList with duplicates,
-  toAscList ordering, unionWith, foldlWithKey).
- [ ] Conformance programs:
+- [x] Unit tests in `lib/haskell/tests/map.sx` (26 tests, well past ≥20 target:
+  empty/singleton/insert/lookup hit&miss/overwrite/delete/member at the SX
+  level, fromList with duplicates last-wins, toAscList ordering, elems in
+  order, unionWith/intersectionWith/difference, foldlWithKey/mapWithKey/
+  filterWithKey, adjust/insertWith/alter, plus 4 end-to-end tests via
+  `import qualified Data.Map as Map`.)
+- [x] Conformance programs:
  - `wordfreq.hs` — word-frequency histogram using `Data.Map`. Source from
    Rosetta Code "Word frequency" Haskell entry.
  - `mapgraph.hs` — adjacency-list BFS using `Data.Map`.

 ### Phase 12 — Data.Set

- [ ] Implement `Data.Set` in `lib/haskell/set.sx`. Use a standalone
+- [x] Implement `Data.Set` in `lib/haskell/set.sx`. Use a standalone
  weight-balanced BST (same structure as Map but no value field) or wrap
-  `Data.Map` with unit values.
- [ ] API: `empty`, `singleton`, `insert`, `delete`, `member`, `fromList`,
+  `Data.Map` with unit values. _Chose the wrapper approach: Set k = Map k ()._
+- [x] API: `empty`, `singleton`, `insert`, `delete`, `member`, `fromList`,
  `toList`, `toAscList`, `size`, `null`, `union`, `intersection`, `difference`,
  `isSubsetOf`, `filter`, `map`, `foldr`, `foldl'`.
- [ ] Module wiring: `import Data.Set` / `import qualified Data.Set as Set`.
- [ ] Unit tests in `lib/haskell/tests/set.sx` (≥ 15 tests: empty, insert,
+- [x] Module wiring: `import Data.Set` / `import qualified Data.Set as Set`.
+- [x] Unit tests in `lib/haskell/tests/set.sx` (17/17, plan ≥15: empty, insert,
  member hit/miss, delete, fromList deduplication, union, intersection,
-  difference, isSubsetOf).
- [ ] Conformance programs:
+  difference, isSubsetOf, plus 4 end-to-end via `import qualified Data.Set`).
+- [x] Conformance programs:
  - `uniquewords.hs` — unique words in a string using `Data.Set`.
  - `setops.hs` — set union/intersection/difference on integer sets;
    exercises all three combining operations.

 ### Phase 13 — `where` in typeclass instances + default methods

- [ ] Verify `where`-clauses in `instance` bodies desugar correctly. The
+- [x] Verify `where`-clauses in `instance` bodies desugar correctly. The
  `hk-bind-decls!` instance arm must call the same where-lifting logic as
  top-level function clauses. Write a targeted test to confirm.
- [ ] Class declarations may include default method implementations. Parser:
+- [x] Class declarations may include default method implementations. Parser:
  `hk-parse-class` collects method decls; eval registers defaults under
  `"__default__ClassName_method"` in the class dict.
- [ ] Instance method lookup: when the instance dict lacks a method, fall back
+- [x] Instance method lookup: when the instance dict lacks a method, fall back
  to the default. Wire this into the dictionary-passing dispatch.
- [ ] `Eq` default: `(/=) x y = not (x == y)`. Verify it works without an
-  explicit `/=` in every Eq instance.
- [ ] `Ord` defaults: `max a b = if a >= b then a else b`, `min a b = if a <=
+- [x] `Eq` default: `(/=) x y = not (x == y)`. Verify it works without an
+  explicit `/=` in every Eq instance. _Verified using a `MyEq`/`myNeq` class
+  + instance test (operator-style `(/=)` is a parser concern; the default
+  mechanism itself is verified)._
+- [x] `Ord` defaults: `max a b = if a >= b then a else b`, `min a b = if a <=
  b then a else b`. Verify.
- [ ] `Num` defaults: `negate x = 0 - x`, `abs x = if x < 0 then negate x else x`,
-  `signum x = if x > 0 then 1 else if x < 0 then -1 else 0`. Verify.
- [ ] Tests in `lib/haskell/tests/class-defaults.sx` (≥ 10 tests).
- [ ] Conformance programs:
+- [x] `Num` defaults: `negate x = 0 - x`, `abs x = if x < 0 then negate x else x`,
+  `signum x = if x > 0 then 1 else if x < 0 then -1 else 0`. Verify. _Verified
+  for negate / abs via a `MyNum` class. Zero-arity class members like
+  `zero :: a` aren't dispatchable in our 1-arg type-driven scheme; tests
+  derive zero via `(mySub x x)` instead. signum tests skipped — needs
+  `signum` literal handling that's too tied to Phase 10's int/float design._
+- [x] Tests in `lib/haskell/tests/class-defaults.sx` (13/13, plan ≥10).
+- [x] Conformance programs:
  - `shapes.hs` — `class Area a` with a default `perimeter`; two instances
    using `where`-local helpers.

 ### Phase 14 — Record syntax

- [ ] Parser: extend `hk-parse-data` to recognise `{ field :: Type, … }`
+- [x] Parser: extend `hk-parse-data` to recognise `{ field :: Type, … }`
  constructor bodies. AST node: `(:con-rec CNAME [(FNAME TYPE) …])`.
- [ ] Desugar: `:con-rec` → positional `:con-def` plus generated accessor
+- [x] Desugar: `:con-rec` → positional `:con-def` plus generated accessor
  functions `(\rec -> case rec of …)` for each field name.
- [ ] Record creation `Foo { bar = 1, baz = "x" }` parsed as
+- [x] Record creation `Foo { bar = 1, baz = "x" }` parsed as
  `(:rec-create CON [(FNAME EXPR) …])`. Eval builds the same tagged list as
  positional construction (field order from the data decl).
- [ ] Record update `r { field = v }` parsed as `(:rec-update EXPR [(FNAME EXPR)])`.
+- [x] Record update `r { field = v }` parsed as `(:rec-update EXPR [(FNAME EXPR)])`.
  Eval forces the record, replaces the relevant positional slot, returns a new
  tagged list. Field → index mapping stored in `hk-constructors` at registration.
- [ ] Exhaustive record patterns: `Foo { bar = b }` in case binds `b`,
+  _Field map lives in `hk-record-fields` (desugar.sx) for load-order reasons,
+  not `hk-constructors`._
+- [x] Exhaustive record patterns: `Foo { bar = b }` in case binds `b`,
  wildcards remaining fields.
- [ ] Tests in `lib/haskell/tests/records.sx` (≥ 12 tests: creation, accessor,
-  update one field, update two fields, record pattern, `deriving Show` on
-  record type).
- [ ] Conformance programs:
+- [x] Tests in `lib/haskell/tests/records.sx` (14/14, plan ≥12: creation
+  with reorder, accessors, single + two-field update, case-alt + fun-LHS
+  record patterns, `deriving Show` on record types).
+- [x] Conformance programs:
  - `person.hs` — `data Person = Person { name :: String, age :: Int }` with
    accessors, update, `deriving Show`.
  - `config.hs` — multi-field config record; partial update; defaultConfig
@@ -241,19 +272,19 @@ No OCaml changes are needed. The view type is fully representable as an SX dict.

 ### Phase 15 — IORef

- [ ] `IORef a` representation: a dict `{:hk-ioref true :hk-value v}`.
+- [x] `IORef a` representation: a dict `{:hk-ioref true :hk-value v}`.
  Allocation creates a new dict in the IO monad. Mutation via `dict-set!`.
- [ ] `newIORef :: a -> IO (IORef a)` — wraps a new dict in `IO`.
- [ ] `readIORef :: IORef a -> IO a` — returns `(IO (get ref ":hk-value"))`.
- [ ] `writeIORef :: IORef a -> a -> IO ()` — `(dict-set! ref ":hk-value" v)`,
+- [x] `newIORef :: a -> IO (IORef a)` — wraps a new dict in `IO`.
+- [x] `readIORef :: IORef a -> IO a` — returns `(IO (get ref ":hk-value"))`.
+- [x] `writeIORef :: IORef a -> a -> IO ()` — `(dict-set! ref ":hk-value" v)`,
  returns `(IO ("Tuple"))`.
- [ ] `modifyIORef :: IORef a -> (a -> a) -> IO ()` — read + apply + write.
- [ ] `modifyIORef' :: IORef a -> (a -> a) -> IO ()` — strict variant (force
+- [x] `modifyIORef :: IORef a -> (a -> a) -> IO ()` — read + apply + write.
+- [x] `modifyIORef' :: IORef a -> (a -> a) -> IO ()` — strict variant (force
  new value before write).
- [ ] `Data.IORef` module wiring.
- [ ] Tests in `lib/haskell/tests/ioref.sx` (≥ 10 tests: new+read, write,
+- [x] `Data.IORef` module wiring.
+- [x] Tests in `lib/haskell/tests/ioref.sx` (≥ 10 tests: new+read, write,
  modify, modifyStrict, shared ref across do-steps, counter loop).
- [ ] Conformance programs:
+- [x] Conformance programs:
  - `counter.hs` — mutable counter via `IORef Int`; increment in a recursive
    IO loop; read at end.
  - `accumulate.hs` — accumulate results into `IORef [Int]` inside a mapped
@@ -261,25 +292,670 @@ No OCaml changes are needed. The view type is fully representable as an SX dict.

 ### Phase 16 — Exception handling

- [ ] `SomeException` type: `data SomeException = SomeException String`.
+- [x] `SomeException` type: `data SomeException = SomeException String`.
  `IOException = SomeException`.
- [ ] `throwIO :: Exception e => e -> IO a` — raises `("hk-exception" e)`.
- [ ] `evaluate :: a -> IO a` — forces arg strictly; any embedded `hk-error`
+- [x] `throwIO :: Exception e => e -> IO a` — raises `("hk-exception" e)`.
+- [x] `evaluate :: a -> IO a` — forces arg strictly; any embedded `hk-error`
  surfaces as a catchable `SomeException`.
- [ ] `catch :: Exception e => IO a -> (e -> IO a) -> IO a` — wraps action in
+- [x] `catch :: Exception e => IO a -> (e -> IO a) -> IO a` — wraps action in
  SX `guard`; on `hk-error` or `hk-exception`, calls the handler with a
  `SomeException` value.
- [ ] `try :: Exception e => IO a -> IO (Either e a)` — returns `Right v` on
+- [x] `try :: Exception e => IO a -> IO (Either e a)` — returns `Right v` on
  success, `Left e` on any exception.
- [ ] `handle = flip catch`.
- [ ] Tests in `lib/haskell/tests/exceptions.sx` (≥ 10 tests: catch success,
+- [x] `handle = flip catch`.
+- [x] Tests in `lib/haskell/tests/exceptions.sx` (≥ 10 tests: catch success,
  catch error, try Right, try Left, nested catch, evaluate surfaces error,
  throwIO propagates, handle alias).
- [ ] Conformance programs:
+- [x] Conformance programs:
  - `safediv.hs` — safe division using `catch`; divide-by-zero raises,
    handler returns 0.
  - `trycatch.hs` — `try` pattern: run an action, branch on Left/Right.

+### Phase 17 — Parser polish
+
+Real Haskell programs use these on every page; closing the gaps unblocks
+larger conformance programs and removes one-line workarounds in test sources.
+
+- [x] Type annotations in expressions: `(x :: Int)`, `f (1 :: Int)`,
+  `return (42 :: Int)`. Parser currently rejects `::` in `aexp` position;
+  desugar should drop the annotation (we have no inference at this layer
+  yet, so it's a parse-only pass-through).
+- [x] `import` declarations anywhere at the start of a module — currently
+  only the very-top-of-file form is recognised. Real test programs that
+  mix prelude code with `import qualified Data.IORef` need this.
+- [ ] Multi-line top-level `where` blocks (`where { ... }` with explicit
+  braces and semicolons, in addition to the layout-driven form).
+- [ ] Tests for the above in `lib/haskell/tests/parse-extras.sx` (≥ 8).
+
+### Phase 18 — One ambitious conformance program
+
+Pick something nontrivial that exercises feature interactions the small
+suites miss; this is the only way to find unknown-unknown bugs.
+
+- [ ] Choose a target. Candidates:
+  - **Tiny lambda-calculus interpreter** (~80 LOC): parser, eval, env,
+    test cases. Stresses ADTs + records + recursion + `IORef` for state.
+  - **Dijkstra shortest-path** on a small graph using `Data.Map` +
+    `Data.Set`. Stresses Map/Set correctness end-to-end.
+  - **JSON parser** (subset): recursive-descent, exception-on-error,
+    `Either ParseError Value` results. Stresses strings + Either + try.
+- [ ] Adapt minimally; cite source as a comment.
+- [ ] Add to `conformance.conf`; verify scoreboard stays green.
+
+### Phase 19 — Conformance speed
+
+The full suite re-pays the ~30 s cold-load cost per program; 36 programs ⇒
+~25 minutes. Driving them all through one sx_server session would compress
+that to single-digit minutes.
+
+- [ ] In `conformance.sh` (and/or `lib/guest/conformance.sh`), batch all
+  suites into one process: load preloads once, then for each suite emit
+  an `(epoch N)` + `(load …)` + `(eval read-counters)` + `(eval reset-
+  counters)` block. Aggregate the per-suite results from the streamed
+  output.
+- [ ] Make sure a single failing/hanging suite doesn't poison the rest —
+  per-suite timeout via a server-side guard, or fall back to per-process
+  on timeout.
+- [ ] Verify the scoreboard output is byte-identical to the old per-process
+  driver, then keep the per-process path as `--isolated` for debugging.
+
+### Phase 20 — Close Algorithm W gaps
+
+`lib/haskell/infer.sx` already implements core HM (TVar/TCon/TArr/TApp/TTuple/
+TScheme, substitution, occurs-check unification, instantiate/generalize, let-
+polymorphism). 75 inference unit tests + 15 typecheck integration tests pass.
+The remaining gaps that block typing real programs:
+
+- [ ] `case` expressions in `hk-w`. Needs to infer scrutinee type, then for
+  each `(:alt pat body)` infer the pattern's binding env (extending
+  `hk-w-pat`) and unify body types across alts.
+- [ ] `do` notation: extend `hk-type-env0` with `return :: a -> IO a`,
+  `(>>=) :: IO a -> (a -> IO b) -> IO b`, `(>>) :: IO a -> IO b -> IO b`,
+  and primitive IO actions (`putStrLn :: String -> IO ()`,
+  `getLine :: IO String`, etc.). May need a `TApp (TCon "IO") a` shape.
+- [ ] Record-accessor desugaring leaves `__rec_field` placeholder visible to
+  inference. Either skip generated accessor clauses during `hk-infer-prog`
+  or rewrite the desugar to produce a typed shape.
+- [ ] Type annotations in expressions `(x :: Int)` (parser also needed; see
+  Phase 17). Infer should unify the inferred type with the annotation.
+- [ ] Tests in `lib/haskell/tests/infer-extras.sx` (≥ 10) covering the
+  above shapes.
+
+### Phase 21 — Type classes (Eq, Ord, Num, Show)
+
+The evaluator already implements typeclass dispatch via dict-passing
+(`__default__ClassName_method` + per-instance dicts). The type system
+ignores `class` and `instance` decls. Closing this means HM with
+constraints (qualified types `[ClassName var] => type`).
+
+- [ ] Extend the type representation: `(TQual CONSTRAINTS TYPE)` where
+  `CONSTRAINTS = [(class-name . type-arg), …]`.
+- [ ] Generalize → `forall vars. preds => type`; instantiate → fresh-rename
+  vars in both preds and type.
+- [ ] During inference, when a primitive operator that needs a class is
+  used (e.g. `+`), emit a constraint `(Num t)`; collect constraints in
+  the substitution-threading.
+- [ ] At let-generalization, simplify constraints (defaulting for `Num`
+  literals → `Int`; entailment via known instances).
+- [ ] `class` declarations register members with their qualified type;
+  `instance` declarations register a witness.
+- [ ] At top-level, if any unsolvable constraint remains → type error
+  ("No instance for X").
+- [ ] Tests in `lib/haskell/tests/typeclasses.sx` (≥ 12 covering Eq, Ord,
+  Num overloading, show on instances, instance ambiguity rejection).
+
+### Phase 22 — Typecheck-then-run as the default
+
+- [ ] Replace `hk-run` with a typecheck-first variant in the conformance
+  driver, or run conformance twice (once typed, once untyped) and report
+  both pass-rates in `scoreboard.md`.
+- [ ] Investigate which existing 36 programs are untypeable due to gaps
+  closed in Phase 20-21 vs genuinely dynamically-typed; aim for ≥ 30/36
+  programs typechecking before committing to the swap.
+- [ ] If swap is committed, retire `hk-run` callsites in tests in favour
+  of `hk-run-typed`; keep the untyped path available for parser/eval
+  development against in-progress features.
+
 ## Progress log

 _Newest first._
+
+**2026-05-10** — Phase 17 second box: `import` declarations anywhere among
+top-level decls. `hk-collect-module-body` previously ran a fixed
+import-loop at the start, then a separate decl-loop; merged into a single
+`hk-body-step` dispatcher that routes `import` to the imports list and
+everything else to `hk-parse-decl`. Each call site (initial step + post-
+semicolon loop) now uses the dispatcher. Imports collected mid-stream
+still feed into `hk-bind-decls!` correctly because the eval side reads
+them via the imports list, not by AST position. tests/parse-extras.sx
+12 → 17 covering very-top, mid-stream, post-main, two-imports-different-
+positions, and unqualified mid-file. Regression: eval 66/0, exceptions
+14/0, typecheck 15/0, records 14/0, ioref 13/0, map 26/0, set 17/0.
+
+**2026-05-08** — Phase 17 first box: expression type annotations `(x :: Int)`,
+`f (1 :: Int)`, `(\x -> x+1) :: Int -> Int`. Parser's `hk-parse-parens`
+gains a `::` arm after the first inner expression: consume `::`, parse a
+type via the existing `hk-parse-type`, expect `)`, emit `(:type-ann EXPR
+TYPE)`. Desugar drops the annotation — `:type-ann E _ → (hk-desugar E)` —
+since the existing eval path has no type-directed dispatch; Phase 20 will
+let inference consume the annotation. tests/parse-extras.sx 12/12; eval,
+exceptions, typecheck, records, ioref still clean.
+
+**2026-05-08** — Plan extends with Phases 20-22 (HM type system). Discovered
+during planning that `lib/haskell/infer.sx` already lands core Algorithm W
+(75 inference unit tests pass; let-polymorphism, sig checking, error
+reporting via `hk-expr->brief`). Fixed five regressing tests in
+`lib/haskell/tests/typecheck.sx` that compared an unforced thunk against
+the expected value — added `hk-deep-force` around `hk-run-typed` to match
+the existing untyped-path convention. typecheck.sx now 15/15.
+Phase 20 captures the remaining Algorithm W gaps (case, do, record
+accessors, expression annotations); Phase 21 captures type classes with
+qualified types; Phase 22 captures the integration step (typecheck-then-run
+across conformance).
+
+**2026-05-08** — Phase 16 Exception handling complete (6 ops + module wiring +
+14 unit tests + 2 conformance programs). `hk-bind-exceptions!` in `eval.sx`
+registers `throwIO`, `throw`, `evaluate`, `catch`, `try`, `handle`, and
+`displayException`. `SomeException` constructor pre-registered in
+`runtime.sx`. `throwIO` and the `error` primitive both raise via SX `raise`
+with a uniform `"hk-error: msg"` string; catch/try/handle parse this string
+back into a `SomeException` via `hk-exception-of` (which strips nested
+`Unhandled exception: "..."` host wraps and the `hk-error: ` prefix). catch
+and handle evaluate the handler outside the guard scope, so a re-throw from
+the handler propagates past this catch (matching Haskell semantics, not an
+infinite loop). Phase 16 phase complete: scoreboard now 285/285 tests,
+36/36 programs.
+
+**2026-05-07** — Fix string ↔ `[Char]` equality. `reverse`/`length`/`head`/etc.
+on a string transparently coerce to a cons-list of char codes via `hk-str-head`
+ `hk-str-tail`, but `(==)` then compared the original raw string against the
+char-code cons-list and always returned False. Added `hk-try-charlist-to-string`
+ `hk-normalize-for-eq` in `eval.sx` and routed `==` / `/=` through them, so a
+string compares equal to any cons-list whose elements are valid Unicode code
+points spelling the same characters (and `[]` ↔ `""`). palindrome.hs now 12/12;
+conformance lifts to 34/34 programs, **269/269 tests** — full green.
+
+**2026-05-07** — Phase 15 IORef complete (5 ops + module wiring + 13 unit
+tests + 2 conformance programs). `hk-bind-data-ioref!` in `eval.sx` registers
+`newIORef`, `readIORef`, `writeIORef`, `modifyIORef`, `modifyIORef'` under the
+import alias (default `IORef`). Representation: dict `{"hk-ioref" true
+"hk-value" v}` allocated inside `IO`. Side-effect: fixed a pre-existing bug
+in the import handler — `modname` was reading `(nth d 1)` (the qualified
+flag) instead of `(nth d 2)`, so all `import qualified … as Foo` paths were
+silently no-ops; map.sx unit suite jumps from 22→26 passing as a result.
+Conformance now 33/34 programs (counter 7/7, accumulate 8/8 added; only
+pre-existing palindrome 9/12 still failing on string-as-list reversal).
+
+**2026-05-07** — Phase 14 conformance: person.hs (7/7) + config.hs (10/10) → Phase 14 complete:
+- `program-person.sx`: classic Person record with `birthday p = p { age = age p + 1 }`
+  exercising the read-then-update idiom on a CAF instance, plus `deriving Show`
+  output.
+- `program-config.sx`: 4-field Config record with defaultConfig CAF, two
+  derived configs via partial update (devConfig flips one Bool, remoteConfig
+  changes two String/Int fields). 10 tests covering both branches preserve
+  the unchanged fields.
+- Both added to `PROGRAMS` in `conformance.sh`. Phase 14 fully complete.
+
+**2026-05-07** — Phase 14 unit tests `tests/records.sx` (14/14):
+- Covers creation (with field reorder), accessors, single-field update,
+  two-field update, case-alt + fun-LHS record patterns, and `deriving Show`
+  on record types (which produces the expected positional `Person "alice" 30`
+  format since records desugar to positional constructors).
+
+**2026-05-07** — Phase 14 record patterns `Foo { bar = b }`:
+- Parser: `hk-parse-pat-lhs` now peeks for `{` after a conid; if found, calls
+  `hk-parse-rec-pat` which collects `(fname pat)` pairs and emits `:p-rec`.
+- Desugar: `:p-rec` → `:p-con` with positional pattern args; missing fields
+  become `:p-wild`s. The `:alt` desugar case now also recurses into the
+  pattern (was only desugaring the body); the `:fun-clause` case maps
+  desugar over its param patterns. Both needed for the field-name → index
+  lookup to fire on `:p-rec` nodes inside case alts and function clauses.
+- Verified end-to-end: case-alt record patterns, multi-field bindings, and
+  function-LHS record patterns all work. No regressions in match (31/31),
+  eval (66/66), desugar (15/15), deriving (15/15), quicksort (5/5).
+
+**2026-05-07** — Phase 14 record-update syntax `r { field = v }`:
+- Parser: `varid {` after a primary expression now triggers
+  `hk-parse-rec-update` returning `(:rec-update record-expr [(fname expr) …])`.
+  (Generalising to arbitrary base expressions is future work — `var` covers
+  the common case.)
+- Desugar: a `:rec-update` node passes through with both record-expr and
+  field-expr children desugared.
+- Eval: forces the record, walks its positional args alongside the field
+  list (from `hk-record-fields`) to find which slots are being overridden,
+  builds a fresh tagged-list value with new thunks for the changed fields
+  and the original args otherwise. Multi-field update works. Verified end-
+  to-end on `alice { age = 31 }` (only age changes; name preserved). No
+  regressions in eval / match / desugar suites.
+
+**2026-05-07** — Phase 14 record-creation syntax `Foo { f = e, … }`:
+- Parser: post-`conid` peek for `{` triggers `hk-parse-rec-create`, returning
+  `(:rec-create cname [(fname expr) …])`.
+- `hk-record-fields` dict (in desugar.sx — load order requires it live there)
+  is populated by `hk-expand-records` when it sees a `con-rec`.
+- New `:rec-create` case in `hk-desugar` looks up the field order, builds an
+  `app` chain `(:app (:app (:con cname) e1) e2 …)` in declared order. Field-
+  pair lookup via new `hk-find-rec-pair` helper. Order in source doesn't
+  matter — `Person { age = 99, name = "bob" }` correctly produces a Person
+  with name="bob", age=99 regardless of source order.
+- Verified via direct execution; no regressions in parse/desugar/deriving.
+
+**2026-05-07** — Phase 14 record desugar (`:con-rec` → positional + accessors):
+- New `hk-record-accessors` helper in `desugar.sx` generates one fun-clause
+  per field, pattern-matching on the constructor with wildcards in all other
+  positions.
+- New `hk-expand-records` walks the decls list pre-desugar; `data` decls with
+  `con-rec` get their constructor rewritten to `con-def` (just the types) and
+  accessor fun-clauses appended after the data decl. Other decls pass through.
+- Wired into the `program` and `module` cases of `hk-desugar`. End-to-end:
+  `data Person = Person { name :: String, age :: Int }` + `name (Person "alice" 30)`
+  returns `"alice"`, `age (Person "bob" 25)` returns `25`. No regressions in
+  parse / desugar / deriving.
+
+**2026-05-07** — Phase 14 record parser: `data Foo = Foo { name :: T, … }`:
+- Extended `hk-parse-con-def` to peek for `{` after the constructor name; if
+  found, parse `varid :: type` pairs separated by commas, terminate with `}`,
+  return `(:con-rec name [(fname ftype) …])`. Positional constructors fall
+  through to the existing `:con-def` path. Verified record parses; no
+  regressions in parse.sx (43/43), parser-decls (24/24), deriving (15/15).
+
+**2026-05-07** — Phase 13 conformance: shapes.hs (5/5) → Phase 13 complete:
+- `class Shape` with a default `perimeter` (using a where-clause inside the
+  default body), two instances `Square` / `Rect` — Square overrides
+  `perimeter`, Rect's `perimeter` uses a where-bound `peri`. 5/5 across
+  area, perimeter (override), perimeter-via-where, sum. Phase 13 fully
+  complete.
+
+**2026-05-07** — Phase 13 Num-style default verification (negate/abs):
+- `MyNum` class with subtract + lt as the operating primitives. Defaults for
+  `myNegate x` and `myAbs x` derive zero via `mySub x x`. Zero-arity class
+  methods like `myZero :: a` are not yet supported by our 1-arg type-driven
+  dispatcher (would loop) — documented constraint. 3 new tests, 13/13 total.
+
+**2026-05-07** — Phase 13 Ord-style default verification:
+- Added 5 tests to `class-defaults.sx` for myMax/myMin defined as defaults
+  in terms of `myCmp` (≥). Verified myMax/myMin on (3,5), (8,2), (4,4).
+  Suite is now 10/10.
+
+**2026-05-07** — Phase 13 Eq-style default verification:
+- New `tests/class-defaults.sx` (5 tests) seeds the class-defaults test file.
+  Covers a 2-arg default method (`myNeq x y = not (myEq x y)`) where the
+  instance provides only `myEq`, both Boolean outcomes, instance-method-takes-
+  precedence-over-default, and default fallback when the instance is empty.
+  All 5 pass.
+
+**2026-05-07** — Phase 13 default method implementations + dispatch fallback:
+- class-decl handler now also registers fun-clause method bodies under
+  `__default__ClassName_method` (paralleling the type-sig dispatcher pass).
+- Dispatcher rewritten as nested `if`s: instance dict has the method →
+  use it; else look up default → use it; else raise. Earlier attempt with
+  `cond + and` infinite-looped — switched to plain `if` form which works.
+- Both regular dispatch (`describe x = "a boolean"` instance) and default
+  fallback (`hello x = "hi"` default with empty instance body) verified.
+  No regressions in class/deriving/instance-where/eval suites.
+
+**2026-05-07** — Phase 13 `where`-clauses in `instance` bodies:
+- Bug discovered: `hk-desugar` didn't recurse into `instance-decl` method
+  bodies, so a `where`-form in an instance method survived to eval and hit
+  `eval: unknown node tag 'where'`. Fix: added an `instance-decl` case to
+  the desugarer that maps `hk-desugar` over the method-decls list. The
+  existing `fun-clause` branch then desugars each method body, including
+  the where → let lifting.
+- 4 tests in new `tests/instance-where.sx`: where-helper with literal
+  pattern matching, references reused multiple times, and multi-binding
+  where. Verified no regression in class.sx (14/14), deriving.sx (15/15),
+  desugar.sx (15/15).
+
+**2026-05-07** — Phase 12 conformance: uniquewords.hs (4/4) + setops.hs (8/8) → Phase 12 complete:
+- `program-uniquewords.sx`: `foldl Set.insert` over a word list, then check
+  `Set.size`/`member`. 4/4.
+- `program-setops.sx`: full set algebra — union/intersection/difference/
+  isSubsetOf with three sets s1, s2, s3 chosen so each operation has both a
+  positive and negative test. 8/8.
+- Both added to `PROGRAMS` in `conformance.sh`. Phase 12 fully complete.
+
+**2026-05-07** — Phase 12 unit tests `tests/set.sx` (17/17):
+- 13 SX-level direct calls + 4 end-to-end via `import qualified Data.Set`.
+  Covers all the API + dedupe behavior. Suite is 17/17.
+
+**2026-05-07** — Phase 12 module wiring: `import Data.Set`:
+- New `hk-bind-data-set!` registers `Set.empty/singleton/insert/delete/
+  member/size/null/union/intersection/difference/isSubsetOf` as Haskell
+  builtins.
+- Import handler now dispatches on modname: `Data.Map` → `hk-bind-data-map!`,
+  `Data.Set` → `hk-bind-data-set!`. Default alias is now derived from the
+  modname suffix instead of being hardcoded `Map` (was a bug for `Data.Set`).
+- `test.sh` and `conformance.sh` load `set.sx` after `map.sx`.
+- Verified `Set.size`, `Set.member`, `Set.union`, `Set.insert` from Haskell.
+
+**2026-05-07** — Phase 12 Data.Set full API:
+- Added `from-list`/`union`/`intersection`/`difference`/`is-subset-of`/
+  `filter`/`map`/`foldr`/`foldl` — all delegate to the corresponding
+  `hk-map-*` helpers with the value side ignored. `union`/`intersection`
+  use `hk-map-union-with`/`hk-map-intersection-with` with a constant
+  unit-returning combine fn. Spot-check confirms set semantics: dedupe
+  on fromList, correct ⋃/∩/− and isSubsetOf.
+
+**2026-05-07** — Phase 12 Data.Set skeleton (wraps Data.Map with unit values):
+- New `lib/haskell/set.sx`. `hk-set-empty/singleton/insert/delete/member/
+  size/null/to-list` all delegate to the corresponding `hk-map-*`. Storage
+  representation matches Map nodes; values are always `("Tuple")` (unit).
+  This trades a small per-node memory overhead for a one-line implementation
+  of every set primitive — full BST balancing comes for free. Spot-checked.
+
+**2026-05-07** — Phase 11 conformance: wordfreq.hs (7/7) + mapgraph.hs (6/6) → Phase 11 complete:
+- Extended `hk-bind-data-map!` with `Map.insertWith`, `Map.adjust`, and
+  `Map.findWithDefault` so the conformance programs have what they need.
+- `program-wordfreq.sx`: word-frequency histogram, `foldl Map.insertWith Map.empty`.
+- `program-mapgraph.sx`: adjacency list, `Map.findWithDefault [] n g` for
+  default-empty neighbors.
+- Both added to `PROGRAMS` in `conformance.sh`. Phase 11 fully complete.
+
+**2026-05-07** — Phase 11 unit tests `tests/map.sx` (26/26):
+- 22 SX-level direct calls (empty/singleton/insert/lookup/delete/member/
+  fromList+duplicates/toAscList/elems/unionWith/intersectionWith/difference/
+  foldlWithKey/mapWithKey/filterWithKey/adjust/insertWith/alter) plus 4
+  end-to-end via `import qualified Data.Map as Map`. Plan asked for ≥20.
+
+**2026-05-07** — Phase 11 module wiring: `import Data.Map`:
+- Added `hk-bind-data-map!` helper in `eval.sx` that registers
+  `<alias>.empty/singleton/insert/lookup/member/size/null/delete` as Haskell
+  builtins. Default alias is `"Map"`.
+- New `:import` case in `hk-bind-decls!` dispatches to `hk-bind-data-map!`
+  when modname = `"Data.Map"`. Also fixed `hk-eval-program` to actually
+  process the imports list (was extracting only decls); now it calls
+  `hk-bind-decls!` once on imports, then once on decls.
+- `test.sh` and `conformance.sh` now load `lib/haskell/map.sx` after
+  `eval.sx` so the BST functions exist when the import handler binds.
+- Verified `import qualified Data.Map as Map` and `import Data.Map`
+  (default alias) resolve `Map.empty`, `Map.insert`, `Map.lookup`, `Map.size`,
+  `Map.member` correctly.
+
+**2026-05-07** — Phase 11 updating (adjust/insertWith/insertWithKey/alter):
+- `adjust` recurses to find the key, replaces value with `f(v)`; no-op when
+  missing. `insertWith` and `insertWithKey` recurse with rebalance and use
+  `f new old` (or `f k new old`) when the key exists. `alter` is the most
+  general, implemented as `lookup → f → either delete or insert`.
+
+**2026-05-07** — Phase 11 transforming (foldlWithKey/foldrWithKey/mapWithKey/filterWithKey):
+- Folds traverse in-order. `foldlWithKey f acc m` walks left → key/val → right
+  threading the accumulator, so left-folding `(\acc k v -> acc ++ k ++ v)` over
+  a 3-key map yields `"1a2b3c"`. `foldrWithKey` runs right → key/val → left so
+  the cons-style accumulator `(\k v acc -> k ++ v ++ acc)` produces the same
+  string.
+- `mapWithKey` rebuilds the tree node-by-node (no rebalancing needed — keys
+  unchanged so the existing structure stays valid). `filterWithKey` is a
+  `foldrWithKey` that re-inserts kept entries; rebalances via insert.
+
+**2026-05-07** — Phase 11 combining (unionWith/intersectionWith/difference):
+- All three implemented via `reduce` over the smaller map's `to-asc-list`,
+  inserting / skipping into the result. Verified:
+  union with `(str a "+" b)` produces `b+B` for the shared key; intersection
+  with `(+)` over `[1→10,2→20] ⊓ [2→200,3→30]` yields `(2 220)`; difference
+  preserves `m1` keys absent from `m2`.
+
+**2026-05-07** — Phase 11 bulk operations (fromList/toList/toAscList/keys/elems):
+- `hk-map-from-list` uses SX `reduce` — left-to-right, so duplicates resolve
+  with last-wins (matches GHC `fromList`). `to-asc-list` is in-order recursive
+  traversal returning `(list (list k v) ...)`. `to-list` aliases `to-asc-list`.
+  `keys` and `elems` are similar in-order extracts. All take SX-level pairs;
+  the Haskell-layer wiring (next iterations) translates Haskell cons + tuple
+  representations.
+
+**2026-05-07** — Phase 11 core operations on `Data.Map` BST:
+- Added `hk-map-singleton`, `hk-map-insert`, `hk-map-lookup`, `hk-map-delete`,
+  `hk-map-member`, `hk-map-null`. Insert recurses with `hk-map-balance` to
+  maintain weight invariants. Lookup returns `("Just" v)` / `("Nothing")` —
+  matches Haskell ADT layout. Delete uses a `hk-map-glue` helper that picks
+  the larger subtree and pulls its extreme element to the root, preserving
+  balance without imperative state. Spot-checked: insert+lookup hit/miss,
+  member, delete root with successor pulled from right.
+
+**2026-05-07** — Phase 11 BST skeleton in `lib/haskell/map.sx`:
+- Adams-style weight-balanced tree: node = `("Map-Node" k v l r size)`,
+  empty = `("Map-Empty")`. delta=3 / gamma=2 ratios. Implemented constructors
+  + accessors + the four rotations (single-l, single-r, double-l, double-r)
+  + `hk-map-balance` smart constructor that picks the rotation. Spot-checked
+  with eval calls; user-facing operations (insert/lookup/etc.) come next.
+
+**2026-05-07** — Phase 10 conformance: statistics.hs (5/5) + newton.hs (5/5) → Phase 10 complete:
+- `program-statistics.sx`: mean / variance / stdDev on a [Double], exercising
+  `sum`, `map`, `fromIntegral`, `/`, `sqrt`. 5/5.
+- `program-newton.sx`: Newton's method for sqrt, exercising `abs`, `/`, `*`,
+  recursion termination on tolerance 0.0001, and `(<)` to assert convergence
+  to within 0.001 of the true value. 5/5.
+- Both added to `PROGRAMS` in `conformance.sh`. Phase 10 fully complete.
+
+**2026-05-07** — Phase 10 numerics test file checkbox (filename divergence):
+- Plan called for `lib/haskell/tests/numeric.sx`. From the very first Phase 10
+  iteration I created `numerics.sx` (plural) and have been growing it. Now
+  at 37/37 — already covers all the categories the plan listed, well past the
+  ≥15 minimum. Ticked the box; left a note about the filename divergence.
+
+**2026-05-07** — Phase 10 Floating stub (pi, exp, log, sin, cos, **):
+- pi as a number constant; exp/log/sin/cos as builtins thunking through to SX
+  primitives. `(**)` added as a binop case in `hk-binop` mapping to SX `pow`.
+  6 new tests in `numerics.sx` (now 37/37). `2 ** 10 = 1024`, `log (exp 5) = 5`,
+  `sin 0 = 0`, `cos 0 = 1`, `pi ≈ 3.14159`, `exp 0 = 1`.
+
+**2026-05-07** — Phase 10 Fractional stub (recip, fromRational):
+- `(/)` already a binop. Added `recip` and `fromRational` as builtins
+  post-prelude. 3 new tests in `numerics.sx` (now 31/31).
+
+**2026-05-07** — Phase 10 math builtins (sqrt/floor/ceiling/round/truncate):
+- Inserted in the post-prelude `begin` block so they override the prelude's
+  identity stubs. `ceiling` is the only one needing a definition (SX doesn't
+  ship one — derived from `floor`). `sqrt`, `floor`, `round`, `truncate`
+  thunk through to SX primitives. 6 new tests in `numerics.sx` (now 28/28).
+
+**2026-05-07** — Phase 10 Float display through `hk-show-val`:
+- Added `hk-show-num` and `hk-show-float-sci` helpers in `eval.sx`. Number
+  formatting: `integer?` → decimal (covers all whole-valued numbers, both ints
+  and whole floats); else if `|n| ∉ [0.1, 10^7)` → scientific (`1.0e-3`); else
+  → decimal with `.0` suffix.
+- `show 3.14` = `"3.14"`, `show 0.001` = `"1.0e-3"`, `show -3.14` = `"-3.14"`.
+- Limit: `show 1.0e10` renders as `"10000000000"` instead of `"1.0e10"` —
+  Haskell distinguishes `42` from `42.0` via type, we don't. Documented.
+- 4 new tests in `numerics.sx`. Suite is now 22/22.
+
+**2026-05-07** — Phase 10 `toInteger` / `fromInteger` verified (prelude identities):
+- Both already declared as `x = x` in `hk-prelude-src`. Added 4 tests in
+  `numerics.sx` (positive, identity round-trip, negative-via-negate, fromInteger
+  smoke). Suite now 18/18.
+
+**2026-05-07** — Phase 10 `fromIntegral` verified (already an identity in prelude):
+- Pre-existing `fromIntegral x = x` line in `hk-prelude-src` was already
+  correct — all numbers share one SX type, so the identity implementation is
+  exactly what the plan asked for. Added 4 tests in `numerics.sx` covering:
+  positive int, negative int, mixed-arithmetic, and `map fromIntegral [1,2,3]`.
+  Suite is now 14/14.
+
+**2026-05-07** — Phase 10 large-integer audit (numerics.sx 10/10):
+- Investigated SX number behavior in Haskell context. Findings:
+    • Raw SX `*`, `+`, etc. on two ints stay exact up to ±2^62 (~4.6e18).
+    • The Haskell tokenizer parses any integer literal > 2^53 (~9e15) as
+      a float — so factorial 19 already drifts even though int63 would fit.
+    • Once any operand is float, ops promote and decimal precision is lost.
+    • `Int` and `Integer` both currently map to SX number — no arbitrary
+      precision yet; documented as known limitation.
+- New `tests/numerics.sx` (10 tests): factorials up to 18, products near
+  10^18 (still match via SX's permissive numeric equality), pow 2^62
+  boundary, show/decimal display. Header comment captures the practical
+  limit.
+
+**2026-05-07** — Phase 9 conformance: `partial.hs` (7/7) → Phase 9 complete:
+- New `tests/program-partial.sx` exercising `head []`, `tail []`,
+  `fromJust Nothing`, `undefined`, and user `error` from inside a `do` block;
+  verifies the error message lands in `hk-run-io`'s `io-lines`. Also a happy-
+  path test (`head [42] = 42`) and a "putStrLn before error preserves prior
+  output, never reaches subsequent action" test.
+- Added `partial` to `PROGRAMS` in `conformance.sh`. Phase 9 done.
+
+**2026-05-07** — Phase 9 `tests/errors.sx` (14/14):
+- New file with 14 tests covering: error w/ literal + computed message; error
+  in `if` branch (laziness boundary); undefined via direct + forcing-via-
+  arithmetic + lazy-discard; partial functions head/tail/fromJust; head/tail
+  still working on non-empty input; hk-run-io's caught error landing in
+  io-lines; putStrLn-before-error preserving prior output; hk-test-error
+  substring match. Spec called for ≥10.
+
+**2026-05-07** — Phase 9 `hk-test-error` helper in testlib.sx:
+- New 0-arity-thunk-based assertion: `(hk-test-error name thunk substr)` —
+  evaluates `(thunk)`, expects an exception, checks `index-of` for the given
+  substring in the caught (string-coerced) value. Increments `hk-test-pass` on
+  match, otherwise records into `hk-test-fails` with descriptive expected.
+- Added 2 quick uses to `tests/eval.sx` (error and head []). Suite now 66/66.
+
+**2026-05-07** — Phase 9 `hk-run-io` catches errors, appends to io-lines:
+- Wrapped both `hk-run-io` and `hk-run-io-with-input` in `(guard (e (true …)))`
+  that appends the caught exception to `hk-io-lines`. Also added `hk-deep-force`
+  inside the guard so `main`'s thunk actually evaluates (post-lazy-CAFs change
+  it was a thunk, was previously not forced — IO actions never fired in
+  programs that returned the thunk to `hk-run-io`). Test suites now see error
+  output as the last line of `hk-io-lines` instead of crashing.
+- Updated one io-input test that used an outer `guard` to look for
+  `"file not found"` in the io-lines string instead.
+- Verified across program-io (10/10), io-input (11/11), program-fizzbuzz
+  (12/12), program-calculator (5/5), program-roman (14/14), program-wordcount
+  (10/10), program-showadt (5/5), program-showio (5/5), eval.sx (64/64).
+
+**2026-05-07** — Phase 9 partial functions emit proper error messages:
+- Added empty-list catch clauses to `head`, `tail` in the prelude. Added
+  `fromJust`, `fromMaybe`, `isJust`, `isNothing` (the last three were missing).
+  `fromJust Nothing` raises `"Maybe.fromJust: Nothing"`. Multi-clause dispatch
+  tries the constructor pattern first, then falls through to the empty-list /
+  Nothing error clause.
+- 5 new tests in `tests/eval.sx`. Suite is 64/64. Verified no regressions in
+  match, stdlib, fib, quicksort, program-maybe.
+
+**2026-05-07** — Phase 9 `undefined = error "Prelude.undefined"` + lazy CAFs:
+- Added `undefined = error "Prelude.undefined"` to `hk-prelude-src`. Without
+  any other change this raised at prelude-load time because `hk-bind-decls!`
+  was eagerly evaluating zero-arity definitions (CAFs). Switched the CAF
+  binding from `(hk-eval body env)` to `(hk-mk-thunk body env)` — closer to
+  Haskell semantics: CAFs are not forced until first use.
+- The lazy-CAF change is a small but principled correctness fix; verified
+  no regressions across program-fib (uses `fibs`), program-sieve, primes,
+  infinite, seq, stdlib, class, do-io, quicksort.
+- 2 new tests in `tests/eval.sx` (raises with the right message; `undefined`
+  doesn't fire when not forced via `if True then 42 else undefined`). 59/59.
+
+**2026-05-07** — Phase 9 `error :: String -> a` raises with `hk-error:` prefix:
+- Pre-existing `error` builtin was raising `"*** Exception: <msg>"` (GHC
+  console convention). Renamed prefix to `"hk-error: "` so the wrap-around
+  string SX's `apply` produces (`"Unhandled exception: \"hk-error: ...\""`)
+  contains a stable, searchable tag.
+- Investigation confirmed that the plan's intended `(raise (list "hk-error" msg))`
+  format is mangled by SX `apply` to a string. Plan note added; tests use
+  `index-of` substring matching against the wrapped string.
+- 2 new tests in `tests/eval.sx` (string and computed-message form). Suite
+  is 57/57. Other test suites unchanged (match 31/31, stdlib 48/48, derive
+  15/15, do-io 16/16, class 14/14).
+
+**2026-05-07** — Phase 8 conformance: `showadt.hs` + `showio.hs` (both 5/5):
+- `program-showadt.sx`: `deriving (Show)` on the classic `Expr = Lit | Add | Mul`
+  recursive ADT; tests `print` on three nested expressions and inline `show`
+  spot-checks (negative literal wrapped in parens; fully nested Mul of Adds).
+- `program-showio.sx`: `print` on Int, Bool, list, tuple, Maybe, String, ADT
+  inside a `do` block; verifies one io-line per `print`.
+- Both added to `PROGRAMS` in `conformance.sh`. Phase 8 conformance complete.
+
+**2026-05-07** — Phase 8 `tests/show.sx` expanded to full audit coverage (26/26):
+- 16 new direct `show` tests: Int (positive + negative), Bool (T/F), String,
+  list of Int, empty list, pair tuple, triple tuple, Maybe Nothing, Maybe Just,
+  nested Just (paren wrapping), Just (negate 3) (negative wrapping), nullary
+  ADT, multi-constructor ADT with args, list of Maybe.
+- `show ([] :: [Int])` would be the natural empty-list test but our parser
+  doesn't yet support type ascription; used `show (drop 5 [1,2,3])` instead.
+  Char `'a'` → `"'a'"` deferred to Char-tagging design (Char = Int currently
+  yields `"97"`).
+
+**2026-05-07** — Phase 8 `Read` class stub (`reads`, `readsPrec`, `read`):
+- Three lines added to `hk-prelude-src`: `reads s = []`, `readsPrec _ s = reads s`,
+  `read s = fst (head (reads s))`. The stubs let user code that mentions
+  `reads`/`readsPrec` parse and run; calls succeed by always returning an empty
+  parse list. `read` will throw a pattern-match failure at runtime — fine until
+  Phase 9 `error` lands. No real parser needed per the plan.
+- 3 new tests in `tests/show.sx` (now 10/10).
+
+**2026-05-07** — Phase 8 `showsPrec` / `showParen` / `shows` / `showString` stubs:
+- Added 5 lines to `hk-prelude-src`. `shows x s = show x ++ s`,
+  `showString prefix rest = prefix ++ rest`, `showParen True p s = "(" ++ p (")" ++ s)`,
+  `showParen False p s = p s`, `showsPrec _ x s = show x ++ s`.
+- These let hand-written `Show` instances using `showsPrec`/`showParen` parse
+  and run; the precedence arg is ignored (we always defer to `show`'s built-in
+  precedence handling), but call shapes match Haskell 98 so user code compiles.
+- New `lib/haskell/tests/show.sx` (7 tests). The file is intended to grow to
+  ≥12 covering the full audit (Phase 8 ☐).
+- Function composition `.` is not yet bound; tests use manual composition via
+  let-binding. Address in a later iteration.
+
+**2026-05-06** — Phase 8 `deriving Show` nested constructor parens verified:
+- The Phase 8 audit's precedence-based `hk-show-prec` already does the right
+  thing for `deriving Show`: each constructor arg is shown at prec 11, so any
+  inner constructor with args (or any negative number) gets parenthesised, while
+  nullary constructors and lists/tuples (whose own bracketing is unambiguous)
+  do not. Multi-constructor ADTs (e.g. `Tree = Leaf | Node …`) handled.
+  Records deferred to Phase 14.
+- 4 new tests in `tests/deriving.sx` exercising nested ADT + Maybe-Maybe +
+  negative-arg + list-arg cases; suite is 15/15.
+
+**2026-05-06** — Phase 8 `print` is `putStrLn (show x)` in prelude:
+- Added `print x = putStrLn (show x)` to `hk-prelude-src` and removed the
+  standalone `print` builtin. `print` now resolves through the Haskell-level
+  Prelude path; lazy reference resolution handles the forward call to
+  `putStrLn` (registered after the prelude loads). `show` already calls
+  `hk-show-val` from the Phase 8 audit. do-io / program-fib / program-fizzbuzz
+  remain green.
+
+**2026-05-06** — Phase 8 audit: `hk-show-val` matches Haskell 98 format:
+- `eval.sx`: introduced `hk-show-prec v p` with precedence-based parens.
+  Top-level `show (Just 3)` = `"Just 3"` (no parens); nested `show (Just (Just 3))`
+  = `"Just (Just 3)"` (inner wrapped because called with prec ≥ 11). Negative
+  ints wrapped in parens at high prec for `show (Just (negate 1))` correctness.
+- List/tuple separators changed from `", "` to `","` to match GHC.
+- `hk-show-val` is now a thin shim: `(hk-show-prec v 0)`.
+- Updated `tests/deriving.sx` (3 tests) and `tests/stdlib.sx` (7 tests) to the
+  new format. `Char` single-quote output and string escape for `\n`/`\t`
+  deferred — Char = Int representation prevents disambiguation in show.
+
+**2026-05-06** — Phase 7 conformance complete (runlength-str.hs) + `++` thunk fix:
+- New `lib/haskell/tests/program-runlength-str.sx` (9 tests). Exercises `(x:xs)`
+  pattern matching over Strings, `span` over a string view, tuple `(Int, Char)`
+  construction and `((n,c):rest)` destructuring, `++` between cons spines.
+- `runlength-str` added to `PROGRAMS` in `conformance.sh`.
+- `eval.sx`: `hk-list-append` now `(hk-force a)` on entry. Pre-existing latent
+  bug — when a cons's tail was a thunk (e.g. from the `:` operator inside a
+  recursive Haskell function like `replicateRL n c = c : replicateRL (n-1) c`),
+  the recursion `(hk-list-append (nth a 2) b)` saw a dict, not a list, and
+  raised `"++: not a list"`. Quicksort masked this by chaining `[x]` literals
+  whose tails are forced `("[]")` cells. Forcing in `hk-list-append` is
+  load-bearing for any `++` over a recursively-built spine.
+
+**2026-05-06** — Phase 7 conformance (caesar.hs):
+- New `lib/haskell/tests/program-caesar.sx` (8 tests). Caesar cipher exercising
+  `chr`, `ord`, `isUpper`, `isLower`, `mod`, `map`, and `(x:xs)` pattern matching
+  over native String values via the Phase 7 string-view path. Adapted from
+  https://rosettacode.org/wiki/Caesar_cipher#Haskell.
+- `caesar` added to `PROGRAMS` in `lib/haskell/conformance.sh`. Suite isolated:
+  8/8 passing. Note: `else chr c` in `shift` keeps the char-as-string output type
+  consistent with the alpha branches (pattern bind on a string view yields an int).
+
+**2026-05-06** — Phase 7 complete (string-view O(1) head/tail + `++` native concat):
+- `runtime.sx`: added `hk-str?`, `hk-str-head`, `hk-str-tail`, `hk-str-null?`.
+  String views are `{:hk-str buf :hk-off n}` dicts; native SX strings satisfy the
+  predicate with implicit offset 0. All helpers are O(1) via `char-at` / `string-length`.
+- `eval.sx`: added `chr` (int → single-char string via `char-from-code`), `toUpper`,
+  `toLower` (ASCII-range arithmetic). Fixed `ord` and all char predicates (`isAlpha`,
+  `isAlphaNum`, `isDigit`, `isSpace`, `isUpper`, `isLower`, `digitToInt`) to accept
+  integers from string-view decomposition (not only single-char strings).
+- `match.sx`: cons-pattern `":"` now checks `hk-str?` before the tagged-list path,
+  decomposing to `(hk-str-head, hk-str-tail)`. Empty-list pattern (`p-list []`) also
+  accepts `hk-str-null?` values. `hk-match-list-pat` updated to traverse string views
+  element-by-element.
+- `runtime.sx`: added `hk-str-to-native` (converts view dict to native string via reduce+char-at).
+- `eval.sx`: `hk-list-append` now checks `hk-str?` first; converts both operands via
+  `hk-str-to-native` before native `str` concat. String `++` String no longer builds
+  a cons spine.
+- 35 new tests in `lib/haskell/tests/string-char.sx` (35/35 passing).
+- Full suite: 810/810 tests, 0 regressions (was 775).
--- a/plans/lib-guest.md
+++ b/plans/lib-guest.md
@@ -158,8 +158,8 @@ Extract from `haskell/infer.sx`. Algorithm W or J, generalisation, instantiation
 | 4 — pratt.sx (lua + prolog) | [done] | da27958d | Extracted operator-table format + lookup only — climbing loops stay per-language because lua and prolog use opposite prec conventions. lua/parser.sx: 18-clause cond → 15-entry table. prolog/parser.sx: pl-op-find deleted, pl-op-lookup wraps pratt-op-lookup. lua 185/185, prolog 590/590 — both = baseline. |
 | 5 — ast.sx (lua + prolog) | [partial — pending real consumers] | a774cd26 | Kit + 33 self-tests shipped (10 canonical kinds, predicates, accessors). Step is "Optional" per brief; lua/prolog parsers untouched (185/185 + 590/590). Datalog-on-sx will be the natural first real consumer; lua/prolog converters can land later. |
 | 6 — match.sx (haskell + prolog) | [partial — kit shipped; ports deferred] | 863e9d93 | Pure-functional unify + match kit (canonical wire format + cfg-driven adapters) + 25 self-tests. Existing prolog/haskell engines untouched (structurally divergent — mutating-symmetric vs pure-asymmetric — would risk 746 passing tests under brief's revert-on-regression rule). Real consumer is minikraken/datalog work in flight. |
-| 7 — layout.sx (haskell + synthetic) | [in-progress] | — | — |
-| 8 — hm.sx (haskell + TBD) | [ ] | — | — |
+| 7 — layout.sx (haskell + synthetic) | [partial — haskell port deferred] | d75c61d4 | Configurable kit (haskell-style keyword-opens + python-style trailing-`:`-opens) + 6 self-tests covering both flavours. Synthetic Python-ish fixture passes; haskell/layout.sx untouched (kit not yet a drop-in for Haskell 98 Note 5 etc.; haskell still 156/156 baseline). |
+| 8 — hm.sx (haskell + TBD) | [partial — algebra shipped; assembly deferred] | ab2c40c1 | HM foundations: types/schemes/ftv/apply/compose/generalize/instantiate/fresh-tv on top of match.sx unify, plus literal inference rule. 24/24 self-tests. Algorithm W lambda/app/let assembly deferred to host code — paired sequencing per brief: lib/ocaml/types.sx (OCaml-on-SX Phase 5) + haskell/infer.sx port. Haskell still 156/156 baseline. |

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