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perf(js): validate F32 input before rounding #2015

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Merged
Lorenzobattistela merged 2 commits into from
Nov 3, 2026
Merged

perf(js): validate F32 input before rounding #2015

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88cc6c2
perf(js): validate F32 input before rounding
toprameen Nov 2, 2026
2d08999
test(js): reject long invalid F32 midpoint text
toprameen Nov 2, 2026
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4 changes: 2 additions & 2 deletions bend2/comp.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -6045,8 +6045,8 @@ function f32_from_bits(u) {

function f32_read(s) {
const re = /^[\t\n\v\f\r ]*[+-]?((\d+(?:\.\d*)?|\.\d+)(e[+-]?\d+)?|inf(inity)?|nan)$/i;
const v = f32_round(s.replace(/inf\w*/i, "Infinity"));
return re.test(s) ? {$: "Some", value: v} : {$: "None"};
return re.test(s) ? {$: "Some", value: f32_round(
s.replace(/inf\w*/i, "Infinity"))} : {$: "None"};
}

const f32_round = ${Bend.f32_round};
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15 changes: 10 additions & 5 deletions tests/run/f32_read_long_invalid.bend
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Original file line number Diff line number Diff line change
@@ -1,14 +1,15 @@
# The JS reader must reject a long integer with an invalid suffix without
# splitting its digits between two overlapping repetitions. Build it with
# a tail-recursive accumulator so string construction does not exhaust the stack.
# splitting its digits between two overlapping repetitions. A long decimal
# midpoint with a trailing space must be rejected before exact rounding.
# Build both with a tail-recursive accumulator to avoid exhausting the stack.
import Base

def digits(n: Nat, acc: String) -> String:
def digits(n: Nat, +digit: Char, acc: String) -> String:
match n:
case 0n:
acc
case 1n+p:
digits(p, SCon{'1', acc})
digits(p, digit, SCon{digit, acc})

def seen(m: Maybe<&2, F32>) -> String:
match m:
Expand All @@ -18,6 +19,10 @@ def seen(m: Maybe<&2, F32>) -> String:
F32.show(v)

def main() -> IO(Unit):
IO.print(seen(F32.read(digits(100000n, "x"))))
do IO<Unit>:
IO.print(seen(F32.read(digits(100000n, '1', "x"))))
IO.print(seen(F32.read("1.000000059604644775390625"
++ digits(5000n, '0', " "))))

#|none
#|none