37 lines
817 B
Plaintext
37 lines
817 B
Plaintext
pub fn constant(a: a) -> Fuzzer<a> {
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fn(s0) { Some((s0, a)) }
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}
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pub fn and_then(fuzz_a: Fuzzer<a>, f: fn(a) -> Fuzzer<b>) -> Fuzzer<b> {
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fn(s0) {
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when fuzz_a(s0) is {
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Some((s1, a)) -> f(a)(s1)
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None -> None
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}
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}
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}
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/// Construct a fuzzer that returns values not present in a given list.
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fn nub(n: Int, fuzzer: Fuzzer<a>) -> fn(List<a>) -> Fuzzer<a> {
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fn(st) {
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if n <= 0 {
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fail @"gave up trying to find unique values: the fuzzer did not yield any *new* value after many tries!"
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} else {
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let a <- and_then(fuzzer)
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if False {
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nub(n - 1, fuzzer)(st)
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} else {
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constant(a)
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}
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}
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}
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}
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test thing() {
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let a = 1
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nub(2, constant(a))([])(Seeded { seed: #"01", choices: #"" }) == Some(
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(Seeded { seed: #"01", choices: #"" }, 1),
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)
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}
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