haskell: Phase 8 conformance — showadt.hs + showio.hs (both 5/5)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/haskell/conformance.sh

@@ -20,7 +20,7 @@ if [ ! -x "$SX_SERVER" ]; then
   fi
 fi
 
-PROGRAMS=(fib sieve quicksort nqueens calculator collatz palindrome maybe fizzbuzz anagram roman binary either primes zipwith matrix wordcount powers caesar runlength-str)
+PROGRAMS=(fib sieve quicksort nqueens calculator collatz palindrome maybe fizzbuzz anagram roman binary either primes zipwith matrix wordcount powers caesar runlength-str showadt showio)
 PASS_COUNTS=()
 FAIL_COUNTS=()
 

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}

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}

plans/haskell-completeness.md

@@ -115,7 +115,7 @@ No OCaml changes are needed. The view type is fully representable as an SX dict.
   deriving Show on multi-constructor type, nested constructor parens).
   _Char tests deferred: Char = Int representation; show on a Char is currently
   `"97"` not `"'a'"`._
-- [ ] Conformance programs:
+- [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.
@@ -289,6 +289,14 @@ No OCaml changes are needed. The view type is fully representable as an SX dict.
 
 _Newest first._
 
+**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,