The OP_DIV/numeric-tower work on this branch made the OCaml `/` primitive
return an exact Rational for (/ int int) (e.g. (/ 5 2)=5/2), diverging from
the canonical spec ("/ always returns inexact float"), the test-rationals.sx
header ("in the JS host, (/ int int) returns float — backward-compatible"),
and the JS host itself. That leaked rationals into arithmetic results and
rendered CSS (tw-opacity emitted `opacity:1/20` instead of `0.05`).
Decision (with the user): keep exact rationals as an explicit opt-in
(literals 1/3, make-rational) but bring `/` back into spec/host parity —
the isomorphic SSR↔hydration invariant requires both hosts to agree, and
JS has no native rational type.
- sx_primitives.ml `/`: (/ int int) → integer when exactly divisible, else
inexact float; a Rational operand still yields an exact rational (matches
test-numeric-tower: (/ 6 2)=3, (/ 1 4)=0.25, (/ 5 2)=2.5, (/ 1/2 2)=1/4).
- sx_primitives.ml number? / exact?: recognise the Rational type (real bugs —
test-rationals asserts (number? 1/3) and (exact? 1/3); inexact?/float?
already returned false for Rational, correct).
- sx_vm.ml OP_DIV: comment updated (it delegates to the now-float `/`).
- test-rationals.sx: fix typo in "rational * float = float" — used int 2,
should be 2.0 (1/2 * 2 = 1 exact, not a float; name + siblings use floats).
OCaml conformance 4834→4863 (+29 fixed, zero new failures); rationals,
numeric-tower, arithmetic, tw-opacity suites all 0 failures. Remaining run_tests
failures are the pre-existing environmental hyperscript (host-call-fn) set.
JS host already handles number?/exact? on rationals and float `/`; its
remaining float?/contagion failures are a separate pre-existing limitation
(JS has no distinct float type), out of scope here.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
giles
e90c8fdd97