haskell: 13 new program suites + scoreboard 156/156 (775 tests)

collatz, palindrome, maybe, fizzbuzz, anagram, roman, binary, either,
primes, zipwith, matrix, wordcount, powers — all 18/18 programs green.
conformance.sh PROGRAMS array updated; scoreboard.md regenerated.

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

lib/haskell/tests/program-either.sx

@@ -0,0 +1,83 @@
+;; either.hs — Either ADT operations via pattern matching.
+
+(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-either-src
+  "safeDiv _ 0 = Left \"divide by zero\"\nsafeDiv x y = Right (x `div` y)\n\nfromRight _ (Right x) = x\nfromRight def (Left _) = def\n\nfromLeft (Left x) _ = x\nfromLeft _ def = def\n\nisRight (Right _) = True\nisRight (Left _) = False\n\nisLeft (Left _) = True\nisLeft (Right _) = False\n\nmapRight _ (Left e) = Left e\nmapRight f (Right x) = Right (f x)\n\ndouble x = x * 2\n")
+
+(hk-test
+  "safeDiv 10 2 = Right 5"
+  (hk-prog-val (str hk-either-src "r = safeDiv 10 2\n") "r")
+  (list "Right" 5))
+
+(hk-test
+  "safeDiv 7 0 = Left msg"
+  (hk-prog-val (str hk-either-src "r = safeDiv 7 0\n") "r")
+  (list "Left" "divide by zero"))
+
+(hk-test
+  "fromRight 0 (Right 42) = 42"
+  (hk-prog-val (str hk-either-src "r = fromRight 0 (Right 42)\n") "r")
+  42)
+
+(hk-test
+  "fromRight 0 (Left msg) = 0"
+  (hk-prog-val (str hk-either-src "r = fromRight 0 (Left \"err\")\n") "r")
+  0)
+
+(hk-test
+  "isRight (Right 1) = True"
+  (hk-prog-val (str hk-either-src "r = isRight (Right 1)\n") "r")
+  (list "True"))
+
+(hk-test
+  "isRight (Left x) = False"
+  (hk-prog-val (str hk-either-src "r = isRight (Left \"x\")\n") "r")
+  (list "False"))
+
+(hk-test
+  "isLeft (Left x) = True"
+  (hk-prog-val (str hk-either-src "r = isLeft (Left \"x\")\n") "r")
+  (list "True"))
+
+(hk-test
+  "isLeft (Right x) = False"
+  (hk-prog-val (str hk-either-src "r = isLeft (Right 1)\n") "r")
+  (list "False"))
+
+(hk-test
+  "mapRight double (Right 5) = Right 10"
+  (hk-prog-val (str hk-either-src "r = mapRight double (Right 5)\n") "r")
+  (list "Right" 10))
+
+(hk-test
+  "mapRight double (Left e) = Left e"
+  (hk-prog-val (str hk-either-src "r = mapRight double (Left \"err\")\n") "r")
+  (list "Left" "err"))
+
+(hk-test
+  "chain safeDiv results"
+  (hk-prog-val (str hk-either-src "r = fromRight (-1) (safeDiv 20 4)\n") "r")
+  5)
+
+(hk-test
+  "chain safeDiv error"
+  (hk-prog-val (str hk-either-src "r = fromRight (-1) (safeDiv 20 0)\n") "r")
+  -1)
+
+{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}