haskell: Phase 10 — Floating stub: pi, exp, log, sin, cos, ** (+6 tests, 37/37)

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

lib/haskell/eval.sx

@@ -440,6 +440,7 @@
       ((= op "div") (floor (/ lv rv)))
       ((= op "rem") (mod lv rv))
       ((= op "quot") (truncate (/ lv rv)))
+      ((= op "**") (pow lv rv))
       ((= op ">>=")
         (if
           (and (list? lv) (= (first lv) "IO"))
@@ -814,6 +815,11 @@
           env
           "fromRational"
           (hk-mk-builtin "fromRational" (fn (x) x) 1))
+        (dict-set! env "pi" 3.14159)
+        (dict-set! env "exp" (hk-mk-builtin "exp" (fn (x) (exp x)) 1))
+        (dict-set! env "log" (hk-mk-builtin "log" (fn (x) (log x)) 1))
+        (dict-set! env "sin" (hk-mk-builtin "sin" (fn (x) (sin x)) 1))
+        (dict-set! env "cos" (hk-mk-builtin "cos" (fn (x) (cos x)) 1))
         (let
           ((--sx-to-hk-- (fn (lst) (if (empty? lst) (list "[]") (list ":" (first lst) (--sx-to-hk-- (rest lst))))))
             (--words--

lib/haskell/tests/numerics.sx

@@ -165,4 +165,16 @@
   (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}

plans/haskell-completeness.md

@@ -165,7 +165,7 @@ No OCaml changes are needed. The view type is fully representable as an SX dict.
 - [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._
-- [ ] `Floating` typeclass stub: `pi`, `exp`, `log`, `sin`, `cos`, `(**)`
+- [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,
@@ -303,6 +303,12 @@ No OCaml changes are needed. The view type is fully representable as an SX dict.
 
 _Newest first._
 
+**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).