15 lines
323 B
Plaintext
15 lines
323 B
Plaintext
pub fn foldr(xs: List<a>, f: fn(a, b) -> b, zero: b) -> b {
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when xs is {
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[] -> zero
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[x, ..rest] -> f(x, foldr(rest, f, zero))
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}
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}
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pub fn concat(left: List<a>, right: List<a>) -> List<a> {
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foldr(left, fn(x, xs) { [x, ..xs] }, right)
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}
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test concat_1() {
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concat([1, 2, 3], [4, 5, 6]) == [1, 2, 3, 4, 5, 6]
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}
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