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option: remove map's copy restriction and add map_consume

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Ben Blum 2012-07-17 18:24:51 -04:00
parent 06c42b77d3
commit e57745b48c
1 changed files with 10 additions and 2 deletions
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12
src/libcore/option.rs
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@ -37,12 +37,20 @@ pure fn expect<T: copy>(opt: option<T>, reason: ~str) -> T {
alt opt { some(x) { x } none { fail reason; } }
}
pure fn map<T, U: copy>(opt: option<T>, f: fn(T) -> U) -> option<U> {
pure fn map<T, U>(opt: option<T>, f: fn(T) -> U) -> option<U> {
//! Maps a `some` value from one type to another
alt opt { some(x) { some(f(x)) } none { none } }
}
pure fn map_consume<T, U>(-opt: option<T>, f: fn(-T) -> U) -> option<U> {
/*!
* As `map`, but consumes the option and gives `f` ownership to avoid
* copying.
*/
if opt.is_some() { some(f(option::unwrap(opt))) } else { none }
}
pure fn chain<T, U>(opt: option<T>, f: fn(T) -> option<U>) -> option<U> {
/*!
* Update an optional value by optionally running its content through a
@ -128,7 +136,7 @@ impl extensions<T> for option<T> {
/// Returns true if the option contains some value
pure fn is_some() -> bool { is_some(self) }
/// Maps a `some` value from one type to another
pure fn map<U:copy>(f: fn(T) -> U) -> option<U> { map(self, f) }
pure fn map<U>(f: fn(T) -> U) -> option<U> { map(self, f) }
}
impl extensions<T: copy> for option<T> {