ocaml: phase 6 Float module fleshed out (+6 tests, 598 total)

New Float members:
  zero / one / minus_one
  abs / neg
  add / sub / mul / div     (lift host '+.' '-.' '*.' '/.')
  max / min                 (if-based)
  equal / compare           (Float.compare returns -1 / 0 / 1)
  to_int                    (host floor)
  of_int                    (identity in dynamic runtime)
  of_string                 (delegates to _int_of_string)

Aligns Float with Int's API and lets baselines use Float.add /
Float.compare / etc without lifting the symbols themselves.

  Float.add 3.5 4.5         = 8
  Float.compare 2.5 5.0     = -1
  Float.abs -3.7            = 3.7
  Float.max 3.14 2.71       = 3.14

lib/ocaml/runtime.sx

@@ -630,6 +630,7 @@
 
    module Float = struct
      let to_string f = _string_of_float f
+     let of_string s = _int_of_string s
      let sqrt f = _float_sqrt f
      let sin f = _float_sin f
      let cos f = _float_cos f
@@ -638,6 +639,22 @@
      let ceil f = _float_ceil f
      let round f = _float_round f
      let pi = 3.141592653589793
+     let zero = 0.0
+     let one = 1.0
+     let minus_one = -1.0
+     let abs f = if f < 0.0 then 0.0 -. f else f
+     let neg f = 0.0 -. f
+     let add a b = a +. b
+     let sub a b = a -. b
+     let mul a b = a *. b
+     let div a b = a /. b
+     let max a b = if a > b then a else b
+     let min a b = if a < b then a else b
+     let equal a b = a = b
+     let compare a b =
+       if a < b then -1 else if a > b then 1 else 0
+     let to_int f = _float_floor f
+     let of_int n = n
    end ;;
 
    module Printf = struct

lib/ocaml/test.sh

@@ -1480,6 +1480,20 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 5232)
 (eval "(ocaml-run \"Result.compare compare compare (Ok 1) (Error \\\"fail\\\")\")")
 
+;; ── Float module additions ───────────────────────────────────
+(epoch 5240)
+(eval "(ocaml-run \"Float.add 3.5 4.5\")")
+(epoch 5241)
+(eval "(ocaml-run \"Float.compare 2.5 5.0\")")
+(epoch 5242)
+(eval "(ocaml-run \"Float.abs (-3.7)\")")
+(epoch 5243)
+(eval "(ocaml-run \"Float.max 3.14 2.71\")")
+(epoch 5244)
+(eval "(ocaml-run \"Float.equal 1.5 1.5\")")
+(epoch 5245)
+(eval "(ocaml-run \"Float.zero +. Float.one\")")
+
 EPOCHS
 
 OUTPUT=$(timeout 360 "$SX_SERVER" < "$TMPFILE" 2>/dev/null)
@@ -2354,6 +2368,14 @@ check 5230 "Result.equal Ok 1 Ok 1"       'true'
 check 5231 "Result.compare Ok 5 Ok 3"     '1'
 check 5232 "Result.compare Ok < Error"    '-1'
 
+# ── Float module additions ──────────────────────────────────────
+check 5240 "Float.add 3.5 4.5"            '8'
+check 5241 "Float.compare 2.5 5.0"        '-1'
+check 5242 "Float.abs -3.7"               '3.7'
+check 5243 "Float.max 3.14 2.71"          '3.14'
+check 5244 "Float.equal 1.5 1.5"          'true'
+check 5245 "Float.zero +. Float.one"      '1'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "ok $PASS/$TOTAL OCaml-on-SX tests passed"

plans/ocaml-on-sx.md

@@ -407,6 +407,12 @@ _Newest first._
   binary search tree (`type 'a tree = Leaf | Node of 'a * 'a tree *
   'a tree`) with insert + in-order traversal. Tests parametric ADT,
   recursive match, List.append, List.fold_left.
+- 2026-05-09 Phase 6 — Float module fleshed out (+6 tests, 598
+  total). New Float members: zero, one, minus_one, abs, neg, add,
+  sub, mul, div, max, min, equal, compare, to_int, of_int,
+  of_string. Most just lift the host operators (`+.` is already
+  available as a global). Aligns Float with Int module's API and
+  unblocks idiomatic float arithmetic in baselines.
 - 2026-05-09 Phase 5.1 — balance.ml baseline (paren/bracket/brace
   balance using Stack). is_balanced walks a string; on opener push,
   on closer check stack non-empty + top matches expected opener (else