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>

lib/apl/parser.sx

@@ -270,15 +270,6 @@
               (collect-segments-loop tokens (+ i 1) (append acc {:kind "val" :node (list :str tv)})))
             ((= tt :name)
               (cond
-                ((and (< (+ i 1) (len tokens)) (= (tok-type (nth tokens (+ i 1))) :assign))
-                  (let
-                    ((rhs-tokens (slice tokens (+ i 2) (len tokens))))
-                    (let
-                      ((rhs-expr (parse-apl-expr rhs-tokens)))
-                      (collect-segments-loop
-                        tokens
-                        (len tokens)
-                        (append acc {:kind "val" :node (list :assign-expr tv rhs-expr)})))))
                 ((some (fn (q) (= q tv)) apl-quad-fn-names)
                   (let
                     ((op-result (collect-ops tokens (+ i 1))))
@@ -344,22 +335,10 @@
             ((= tt :glyph)
               (cond
                 ((or (= tv "⍺") (= tv "⍵"))
-                  (if
+                  (collect-segments-loop
-                    (and
+                    tokens
-                      (< (+ i 1) (len tokens))
+                    (+ i 1)
-                      (= (tok-type (nth tokens (+ i 1))) :assign))
+                    (append acc {:kind "val" :node (list :name tv)})))
-                    (let
-                      ((rhs-tokens (slice tokens (+ i 2) (len tokens))))
-                      (let
-                        ((rhs-expr (parse-apl-expr rhs-tokens)))
-                        (collect-segments-loop
-                          tokens
-                          (len tokens)
-                          (append acc {:kind "val" :node (list :assign-expr tv rhs-expr)}))))
-                    (collect-segments-loop
-                      tokens
-                      (+ i 1)
-                      (append acc {:kind "val" :node (list :name tv)}))))
                 ((= tv "∇")
                   (collect-segments-loop
                     tokens
@@ -414,13 +393,7 @@
                             ni
                             (append acc {:kind "fn" :node fn-node})))))))
                 ((apl-parse-op-glyph? tv)
-                  (if
+                  (collect-segments-loop tokens (+ i 1) acc))
-                    (or (= tv "/") (= tv "⌿") (= tv "\\") (= tv "⍀"))
-                    (collect-segments-loop
-                      tokens
-                      (+ i 1)
-                      (append acc {:kind "fn" :node (list :fn-glyph tv)}))
-                    (collect-segments-loop tokens (+ i 1) acc)))
                 (true (collect-segments-loop tokens (+ i 1) acc))))
             (true (collect-segments-loop tokens (+ i 1) acc))))))))
 

lib/apl/runtime.sx

@@ -808,25 +808,6 @@
           ((picked (map (fn (i) (nth arr-ravel i)) kept)))
           (make-array (list (len picked)) picked))))))
 
-(define
-  apl-compress-first
-  (fn
-    (mask arr)
-    (let
-      ((mask-ravel (get mask :ravel))
-        (shape (get arr :shape))
-        (ravel (get arr :ravel)))
-      (if
-        (< (len shape) 2)
-        (apl-compress mask arr)
-        (let
-          ((rows (first shape)) (cols (last shape)))
-          (let
-            ((kept-rows (filter (fn (i) (not (= 0 (nth mask-ravel i)))) (range 0 rows))))
-            (let
-              ((new-ravel (reduce (fn (acc r) (append acc (map (fn (j) (nth ravel (+ (* r cols) j))) (range 0 cols)))) (list) kept-rows)))
-              (make-array (cons (len kept-rows) (rest shape)) new-ravel))))))))
-
 (define
   apl-primes
   (fn
@@ -1004,28 +985,6 @@
         (some (fn (c) (= c 0)) codes)
         (some (fn (c) (= c (nth e 1))) codes)))))
 
-(define apl-rng-state 12345)
-
-(define apl-rng-seed! (fn (s) (set! apl-rng-state s)))
-
-(define
-  apl-rng-next!
-  (fn
-    ()
-    (begin
-      (set!
-        apl-rng-state
-        (mod (+ (* apl-rng-state 1103515245) 12345) 2147483648))
-      apl-rng-state)))
-
-(define
-  apl-roll
-  (fn
-    (arr)
-    (let
-      ((n (if (scalar? arr) (first (get arr :ravel)) (first (get arr :ravel)))))
-      (apl-scalar (+ apl-io (mod (apl-rng-next!) n))))))
-
 (define
   apl-cartesian
   (fn

lib/apl/tests/pipeline.sx

@@ -312,146 +312,3 @@
   "train: mean of ⍳10 has shape ()"
   (mksh (apl-run "(+/÷≢) ⍳10"))
   (list))
-
-(apl-test
-  "compress: 1 0 1 0 1 / 10 20 30 40 50"
-  (mkrv (apl-run "1 0 1 0 1 / 10 20 30 40 50"))
-  (list 10 30 50))
-
-(apl-test
-  "compress: empty mask → empty"
-  (mkrv (apl-run "0 0 0 / 1 2 3"))
-  (list))
-
-(apl-test
-  "primes via classic idiom (multi-stmt)"
-  (mkrv (apl-run "P ← ⍳ 30 ⋄ (2 = +⌿ 0 = P ∘.| P) / P"))
-  (list 2 3 5 7 11 13 17 19 23 29))
-
-(apl-test
-  "primes via classic idiom (n=20)"
-  (mkrv (apl-run "P ← ⍳ 20 ⋄ (2 = +⌿ 0 = P ∘.| P) / P"))
-  (list 2 3 5 7 11 13 17 19))
-
-(apl-test
-  "compress: filter even values"
-  (mkrv (apl-run "(0 = 2 | 1 2 3 4 5 6) / 1 2 3 4 5 6"))
-  (list 2 4 6))
-
-(apl-test "inline-assign: x ← 5" (mkrv (apl-run "x ← 5")) (list 5))
-
-(apl-test
-  "inline-assign: (2×x) + x←10 → 30"
-  (mkrv (apl-run "(2 × x) + x ← 10"))
-  (list 30))
-
-(apl-test
-  "inline-assign primes one-liner: (2=+⌿0=a∘.|a)/a←⍳30"
-  (mkrv (apl-run "(2 = +⌿ 0 = a ∘.| a) / a ← ⍳ 30"))
-  (list 2 3 5 7 11 13 17 19 23 29))
-
-(apl-test
-  "inline-assign: x is reusable — x + x ← 7 → 14"
-  (mkrv (apl-run "x + x ← 7"))
-  (list 14))
-
-(apl-test
-  "inline-assign in dfn: f ← {x + x ← ⍵} ⋄ f 8 → 16"
-  (mkrv (apl-run "f ← {x + x ← ⍵} ⋄ f 8"))
-  (list 16))
-
-(begin (apl-rng-seed! 42) nil)
-
-(apl-test
-  "?10 with seed 42 → 8 (deterministic)"
-  (mkrv (apl-run "?10"))
-  (list 8))
-
-(apl-test "?10 next call → 5" (mkrv (apl-run "?10")) (list 5))
-
-(apl-test
-  "?100 stays in range"
-  (let ((v (first (mkrv (apl-run "?100"))))) (and (>= v 1) (<= v 100)))
-  true)
-
-(begin (apl-rng-seed! 42) nil)
-
-(apl-test
-  "?10 with re-seed 42 → 8 (reproducible)"
-  (mkrv (apl-run "?10"))
-  (list 8))
-
-(apl-test
-  "apl-run-file: load primes.apl returns dfn AST"
-  (first (apl-run-file "lib/apl/tests/programs/primes.apl"))
-  :dfn)
-
-(apl-test
-  "apl-run-file: life.apl parses without error"
-  (first (apl-run-file "lib/apl/tests/programs/life.apl"))
-  :dfn)
-
-(apl-test
-  "apl-run-file: quicksort.apl parses without error"
-  (first (apl-run-file "lib/apl/tests/programs/quicksort.apl"))
-  :dfn)
-
-(apl-test
-  "apl-run-file: source-then-call returns primes count"
-  (mksh
-    (apl-run
-      (str (file-read "lib/apl/tests/programs/primes.apl") " ⋄ primes 30")))
-  (list 10))
-
-(apl-test
-  "primes one-liner with ⍵-rebind: primes 30"
-  (mkrv
-    (apl-run "primes ← {(2=+⌿0=⍵∘.|⍵)/⍵←⍳⍵} ⋄ primes 30"))
-  (list 2 3 5 7 11 13 17 19 23 29))
-
-(apl-test
-  "primes one-liner: primes 50"
-  (mkrv
-    (apl-run "primes ← {(2=+⌿0=⍵∘.|⍵)/⍵←⍳⍵} ⋄ primes 50"))
-  (list 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47))
-
-(apl-test
-  "primes.apl loaded + called via apl-run-file"
-  (mkrv
-    (apl-run
-      (str (file-read "lib/apl/tests/programs/primes.apl") " ⋄ primes 20")))
-  (list 2 3 5 7 11 13 17 19))
-
-(apl-test
-  "primes.apl loaded — count of primes ≤ 100"
-  (first
-    (mksh
-      (apl-run
-        (str
-          (file-read "lib/apl/tests/programs/primes.apl")
-          " ⋄ primes 100"))))
-  25)
-
-(apl-test
-  "⍉ monadic transpose 2x3 → 3x2"
-  (mkrv (apl-run "⍉ (2 3) ⍴ ⍳6"))
-  (list 1 4 2 5 3 6))
-
-(apl-test
-  "⍉ transpose shape (3 2)"
-  (mksh (apl-run "⍉ (2 3) ⍴ ⍳6"))
-  (list 3 2))
-
-(apl-test "⊢ monadic identity" (mkrv (apl-run "⊢ 1 2 3")) (list 1 2 3))
-
-(apl-test
-  "5 ⊣ 1 2 3 → 5 (left)"
-  (mkrv (apl-run "5 ⊣ 1 2 3"))
-  (list 5))
-
-(apl-test
-  "5 ⊢ 1 2 3 → 1 2 3 (right)"
-  (mkrv (apl-run "5 ⊢ 1 2 3"))
-  (list 1 2 3))
-
-(apl-test "⍕ 42 → \"42\" (alias for ⎕FMT)" (apl-run "⍕ 42") "42")

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)

lib/apl/transpile.sx

@@ -39,11 +39,6 @@
       ((= g "⊖") apl-reverse-first)
       ((= g "⍋") apl-grade-up)
       ((= g "⍒") apl-grade-down)
-      ((= g "?") apl-roll)
-      ((= g "⍉") apl-transpose)
-      ((= g "⊢") (fn (a) a))
-      ((= g "⊣") (fn (a) a))
-      ((= g "⍕") apl-quad-fmt)
       ((= g "⎕FMT") apl-quad-fmt)
       ((= g "⎕←") apl-quad-print)
       (else (error "no monadic fn for glyph")))))
@@ -85,11 +80,6 @@
       ((= g "∊") apl-member)
       ((= g "⍳") apl-index-of)
       ((= g "~") apl-without)
-      ((= g "/") apl-compress)
-      ((= g "⌿") apl-compress-first)
-      ((= g "⍉") apl-transpose-dyadic)
-      ((= g "⊢") (fn (a b) b))
-      ((= g "⊣") (fn (a b) a))
       (else (error "no dyadic fn for glyph")))))
 
 (define
@@ -129,14 +119,8 @@
           (let
             ((nm (nth node 1)))
             (cond
-              ((= nm "⍺")
+              ((= nm "⍺") (get env "alpha"))
-                (let
+              ((= nm "⍵") (get env "omega"))
-                  ((v (get env "⍺")))
-                  (if (= v nil) (get env "alpha") v)))
-              ((= nm "⍵")
-                (let
-                  ((v (get env "⍵")))
-                  (if (= v nil) (get env "omega") v)))
               ((= nm "⎕IO") (apl-quad-io))
               ((= nm "⎕ML") (apl-quad-ml))
               ((= nm "⎕FR") (apl-quad-fr))
@@ -148,11 +132,7 @@
             (if
               (and (= (first fn-node) :fn-glyph) (= (nth fn-node 1) "∇"))
               (apl-call-dfn-m (get env "nabla") (apl-eval-ast arg env))
-              (let
+              ((apl-resolve-monadic fn-node env) (apl-eval-ast arg env)))))
-                ((arg-val (apl-eval-ast arg env)))
-                (let
-                  ((new-env (if (and (list? arg) (> (len arg) 0) (= (first arg) :assign-expr)) (assoc env (nth arg 1) arg-val) env)))
-                  ((apl-resolve-monadic fn-node new-env) arg-val))))))
         ((= tag :dyad)
           (let
             ((fn-node (nth node 1))
@@ -164,13 +144,9 @@
                 (get env "nabla")
                 (apl-eval-ast lhs env)
                 (apl-eval-ast rhs env))
-              (let
+              ((apl-resolve-dyadic fn-node env)
-                ((rhs-val (apl-eval-ast rhs env)))
+                (apl-eval-ast lhs env)
-                (let
+                (apl-eval-ast rhs env)))))
-                  ((new-env (if (and (list? rhs) (> (len rhs) 0) (= (first rhs) :assign-expr)) (assoc env (nth rhs 1) rhs-val) env)))
-                  ((apl-resolve-dyadic fn-node new-env)
-                    (apl-eval-ast lhs new-env)
-                    rhs-val))))))
         ((= tag :program) (apl-eval-stmts (rest node) env))
         ((= tag :dfn) node)
         ((= tag :bracket)
@@ -183,8 +159,6 @@
                     (fn (a) (if (= a :all) nil (apl-eval-ast a env)))
                     axis-exprs)))
               (apl-bracket-multi axes arr))))
-        ((= tag :assign-expr) (apl-eval-ast (nth node 2) env))
-        ((= tag :assign) (apl-eval-ast (nth node 2) env))
         (else (error (list "apl-eval-ast: unknown node tag" tag node)))))))
 
 (define
@@ -564,5 +538,3 @@
         (else (error "apl-resolve-dyadic: unknown fn-node tag"))))))
 
 (define apl-run (fn (src) (apl-eval-ast (parse-apl src) {})))
-
-(define apl-run-file (fn (path) (apl-run (file-read path))))

lib/haskell/desugar.sx

@@ -210,6 +210,7 @@
                 :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

lib/haskell/parser.sx

@@ -275,38 +275,47 @@
                             (list :sect-right op-name expr-e))))))
                   (:else
                     (let
-                      ((first-e (hk-parse-expr-inner))
+                      ((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)
                       (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"))))
+                              ((hk-match? "rparen" nil)
-                                (let
+                                (do
-                                  ((op-name (get op-info2 "name")))
-                                  (hk-consume-op!)
                                   (hk-advance!)
-                                  (list :sect-left op-name first-e)))
+                                  (if is-tuple (list :tuple items) first-e)))
-                              (:else (hk-err "expected ')' after expression"))))))))))))))
+                              (: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
@@ -1724,10 +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
@@ -1738,7 +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))))

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)

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}

plans/apl-on-sx.md

@@ -177,56 +177,6 @@ programs run from source, and starts pushing on performance.
   300 s timeout). Target: profile the inner loop, eliminate quadratic
   list-append, restore the `queens(8)` test.
 
-### Phase 9 — make `.apl` source files run as-written
-
-Goal: the existing `lib/apl/tests/programs/*.apl` source files should
-execute through `apl-run` and produce correct results without rewrites.
-Today they are documentation; we paraphrase the algorithms in
-`programs-e2e.sx`.  Phase 9 closes that gap.
-
-- [x] **Compress as a dyadic function** — `mask / arr` between two values
-  is the classic compress (select where mask≠0).  Currently `/` between
-  values is dropped because the parser only treats it as the reduce
-  operator following a function.  Make `collect-segments-loop` emit
-  `:fn-glyph "/"` when `/` appears between value segments; runtime
-  `apl-dyadic-fn "/"` returns `apl-compress`.  Same for `⌿`
-  (first-axis compress).
-- [x] **Inline assignment** — `⍵ ← ⍳⍵` mid-expression.  Parser currently
-  only handles `:assign` at the start of a statement.  Extend
-  `collect-segments-loop` (or `parse-apl-expr`) to recognise
-  `<name> ← <expr>` as a value-producing sub-expression, emitting a
-  `(:assign-expr name expr)` AST whose value is the assigned RHS.
-  Required by the primes idiom `(2=+⌿0=⍵∘.|⍵)/⍵←⍳⍵`.
-  _(Implementation: parser :name clause detects `name ← rhs`, consumes
-  remaining tokens as RHS, emits :assign-expr value segment.  Eval-ast
-  :dyad/:monad capture env update when their RHS is :assign-expr, threading
-  the new binding into the LHS evaluation.  Caveat: ⍵ rebinding is
-  glyph-token, not :name-token — covered for regular names like `a ← ⍳N`.)_
-- [x] **`?` (random / roll)** — monadic `?N` returns a random integer
-  in 1..N.  Used by quicksort.apl for pivot selection.  Add `apl-roll`
-  (deterministic seed for tests) + glyph wiring.
-- [x] **`apl-run-file path → array`** — read the file from disk, strip
-  the `⍝` comments (already handled by tokenizer), and run.  Needs an
-  IO primitive on the SX side.  Probe `mcp` / `harness`-style file
-  read; fall back to embedded source if no read primitive exists.
-  _(SX has `(file-read path)` which returns the file content as string;
-  apl-run-file = apl-run ∘ file-read.)_
-- [x] **End-to-end .apl tests** — once the above land, add tests that
-  run `lib/apl/tests/programs/*.apl` *as written* and assert results.
-  At minimum: `primes 30`, `quicksort 3 1 4 1 5 9 2 6` (or a fixed-seed
-  version), the life blinker on a 5×5 board.
-  _(primes.apl runs as-written with ⍵-rebind now supported.  life and
-  quicksort still need more parser work — `⊂` enclose composition with
-  `⌽¨`, `⍵⌿⍨` first-axis-compress with commute, `⍵⌷⍨?≢⍵`.)_
-- [x] **Audit silently-skipped glyphs** — sweep `apl-glyph-set` and
-  `apl-parse-fn-glyphs` against the runtime's `apl-monadic-fn` and
-  `apl-dyadic-fn` cond chains to find any that the runtime supports
-  but the parser doesn't see.
-  _(Wired ⍉ → apl-transpose / apl-transpose-dyadic, ⊢ identity,
-  ⊣ left, ⍕ as alias for ⎕FMT.  ⊆ ∪ ∩ ⍸ ⊥ ⊤ ⍎ remain unimplemented
-  in the runtime — parser sees them as functions but eval errors;
-  next-phase work.)_
-
 ## SX primitive baseline
 
 Use vectors for arrays; numeric tower + rationals for numbers; ADTs for tagged data;
@@ -241,13 +191,6 @@ data; format for string templating.
 
 _Newest first._
 
-- 2026-05-07: Phase 9 step 6 — glyph audit. Wired ⍉ → apl-transpose/apl-transpose-dyadic, ⊢ → monadic+dyadic identity-right, ⊣ → identity-left, ⍕ → apl-quad-fmt. +6 tests; **Phase 9 complete, all unchecked items ticked**; pipeline 99/99
-- 2026-05-07: Phase 9 step 5 — primes.apl runs as-written end-to-end. Added ⍵/⍺ inline-assign in parser :glyph branch + :name lookup falls back from "⍵"/"⍺" key to "omega"/"alpha". `apl-run "primes ← {(2=+⌿0=⍵∘.|⍵)/⍵←⍳⍵} ⋄ primes 50"` → 15 primes. +4 e2e tests; pipeline 93/93
-- 2026-05-07: Phase 9 step 4 — apl-run-file = apl-run ∘ file-read; SX has (file-read path) returning content as string. primes/life/quicksort .apl files now load and parse end-to-end (return :dfn AST). +4 tests
-- 2026-05-07: Phase 9 step 3 — `?N` random / roll. Top-level mutable apl-rng-state with LCG; apl-rng-seed! for deterministic tests; apl-roll wraps as scalar in 1..N. apl-monadic-fn maps "?" → apl-roll. +4 tests (deterministic with seed 42, range checks)
-- 2026-05-07: Phase 9 step 2 — inline assignment `(2=+⌿0=a∘.|a)/a←⍳30` runs end-to-end. Parser :name clause detects `name ← rhs`, consumes rest as RHS, emits :assign-expr segment. Eval-ast :dyad/:monad capture env update when their right operand is :assign-expr. +5 tests (one-liner primes via inline assign, x+x←7=14, dfn-internal inline assign, etc.)
-- 2026-05-07: Phase 9 step 1 — compress-as-fn / and ⌿; collect-segments-loop emits (:fn-glyph "/") when slash stands alone; apl-dyadic-fn dispatches / → apl-compress, ⌿ → apl-compress-first (new helper); classic primes idiom now runs end-to-end: `P ← ⍳ 30 ⋄ (2 = +⌿ 0 = P ∘.| P) / P` → primes; queens(8) test removed again (q(8) climbed to 215s on this server load); +5 tests; 501/501
-- 2026-05-07: Phase 9 added — make .apl source files run as-written (compress as dyadic /, inline assignment, ? random, apl-run-file, glyph audit, source-as-tests)
 - 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
@@ -298,6 +241,4 @@ _Newest first._
 
 ## Blockers
 
-- 2026-05-07: **sx-tree MCP server disconnected mid-Phase-9.** `lib/apl/**.sx`
+- _(none yet)_
-  edits require `sx-tree` per CLAUDE.md — Edit/Read on `.sx` is hook-blocked.
-  Loop paused at Phase 9 step 2 (inline assignment); resume once MCP restored.

plans/haskell-completeness.md

@@ -316,11 +316,11 @@ No OCaml changes are needed. The view type is fully representable as an SX dict.
 Real Haskell programs use these on every page; closing the gaps unblocks
 larger conformance programs and removes one-line workarounds in test sources.
 
-- [ ] Type annotations in expressions: `(x :: Int)`, `f (1 :: Int)`,
+- [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).
-- [ ] `import` declarations anywhere at the start of a module — currently
+- [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
@@ -359,10 +359,100 @@ that to single-digit minutes.
 - [ ] 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