Mercurial > lbo > hg > memoize
view examples/patterns.rs @ 68:bf87b6014441
Add patterns example
author | Josh <josh.ja.butt@gmail.com> |
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date | Sat, 01 Jan 2022 18:18:17 +1000 |
parents | |
children | 3adb990ef496 |
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use memoize::memoize; // Patterns in memoized function arguments must be bound by name. #[memoize] fn manhattan_distance(_p1 @ (x1, y1): (i32, i32), _p2 @ (x2, y2): (i32, i32)) -> i32 { (x1 - x2).abs() + (y1 - y2).abs() } #[derive(Clone, PartialEq, Eq, Hash)] enum OnlyOne { Value(i32), } #[memoize] fn get_value(_enum @ OnlyOne::Value(value): OnlyOne) -> i32 { value } fn main() { // `manhattan_distance` is only called once here. assert_eq!(manhattan_distance((1, 1), (1, 3)), 2); // Same with `get_value`. assert_eq!(!get_value(OnlyOne::Value(0)), 0); }