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sx/examples/0145-types-integral-float-array-dim.sx
agra e03c087e5a fix(ir): integral-float counts + range-checked value-param binds (0083)
Item 2 (Agra ruling): a compile-time INTEGRAL float (`4.0`, `N : f64 :
4.0`, `N :: 4.0`) used as an array dimension / Vector lane / generic
value-param count / `inline for` bound now folds to its integer at the
shared leaf — `program_index.floatToIntExact`, used by both the
`.float_literal` arm of `evalConstIntExpr` and `moduleConstInt`. All four
consumers route through the one evaluator, so `[4.0]s64` lays out the same
`[4]s64` uniformly; a non-integral (`4.5`) or negative value stays
rejected by the downstream `foldDimU32` gate. Pass-0 now pre-registers
float-valued module consts for forward-alias parity with int consts.

Item 1: a generic value-param bind (`Box($K: u32)`) never range-checked
the folded arg, so `Box(5_000_000_000)` compiled and ran. The bind now
range-checks against the param's declared type — a `u32` count through the
shared `foldDimU32` gate (making program_index's "single u32 gate for
value-param counts" doc true), any other integer type through the new
`program_index.intTypeRange` — and emits a clean "value N does not fit in
u32 parameter K" otherwise. The declared type is threaded via a new
`TemplateParam.value_type`.

Regressions: examples 0145 (integral-float array dim), 1504 (Vector lane),
0611 (inline-for bound), 0209 (value-param integral-float), 1132
(non-integral float dim rejected), 1133 (negative float dim rejected),
1134 (oversized u32 value-param rejected) + program_index float-fold unit
tests. Gate: zig build, zig build test, 406/0 run_examples.
2026-06-04 13:16:39 +03:00

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// An array dimension accepts any compile-time numeric constant whose value is a
// positive INTEGRAL number — an integral float (`4.0`) folds to its integer just
// like `4`. A float-typed const (`N : f64 : 4.0`), an untyped-float const
// (`M :: 4.0`), and a direct float literal (`[4.0]s64`) all lay out the same
// `[4]s64` as the integer spelling, so element store/read is in bounds.
//
// Regression (issue 0083 / F0.4 attempt 8, Agra ruling): an integral float used
// as a dimension was wrongly rejected "must be a compile-time integer constant".
// The shared const-int evaluator now folds an integral float literal (and a
// float-typed module const) via `program_index.floatToIntExact`; a non-integral
// float (`4.5`) is still rejected (see 1132).
#import "modules/std.sx";
N : f64 : 4.0; // float-typed const
M :: 4.0; // untyped float const
main :: () {
a : [N]s64 = ---; // dim from a float-typed const
a[0] = 10; a[3] = 40;
print("a len={} a0={} a3={}\n", a.len, a[0], a[3]);
b : [M]s64 = ---; // dim from an untyped float const
b[1] = 21;
print("b len={} b1={}\n", b.len, b[1]);
c : [4.0]s64 = ---; // direct integral-float-literal dim
c[2] = 32;
print("c len={} c2={}\n", c.len, c[2]);
}