Added filtered method for Option type

This commit is contained in:
Honza Strnad 2013-06-21 21:27:58 +02:00
parent d1927d2950
commit f3966e4a08

View File

@ -159,6 +159,15 @@ impl<T> Option<T> {
}
}
/// Filters an optional value using given function.
#[inline(always)]
pub fn filtered<'a>(self, f: &fn(t: &'a T) -> bool) -> Option<T> {
match self {
Some(x) => if(f(&x)) {Some(x)} else {None},
None => None
}
}
/// Maps a `some` value from one type to another by reference
#[inline(always)]
pub fn map<'a, U>(&self, f: &fn(&'a T) -> U) -> Option<U> {
@ -459,3 +468,11 @@ fn test_get_or_zero() {
let no_stuff: Option<int> = None;
assert_eq!(no_stuff.get_or_zero(), 0);
}
#[test]
fn test_filtered() {
let some_stuff = Some(42);
let modified_stuff = some_stuff.filtered(|&x| {x < 10});
assert_eq!(some_stuff.get(), 42);
assert!(modified_stuff.is_none());
}