21 lines
339 B
Rust
21 lines
339 B
Rust
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type option[T] = tag(none(), some(T));
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type map[T, U] = fn(&T) -> U;
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fn option_map[T, U](map[T, U] f, &option[T] opt) -> option[U] {
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alt (opt) {
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case (some[T](x)) {
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ret some[U](f[T, U](x));
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}
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case (none[T]()) {
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ret none[U]();
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}
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}
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}
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fn id[T](T x) -> T {
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ret x;
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}
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type rational = rec(int num, int den);
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