nordic-dev.net/rust
nordic-dev.net/rust
2
0
Fork 0
mirror of https://github.com/rust-lang/rust.git synced 2024-12-02 03:33:59 +00:00
Code Issues Packages Projects Releases Wiki Activity

core: Add iter::filter_map

Browse Source
This commit is contained in:
Brian Anderson 2012-02-12 22:30:58 -08:00
parent e360ddbd65
commit 8309d50ff4
1 changed files with 25 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
src/libcore/iter.rs
View File

@ -57,6 +57,16 @@ fn filter<A,IA:iterable<A>>(self: IA, prd: fn@(A) -> bool, blk: fn(A)) {
}
}
fn filter_map<A,B,IA:iterable<A>>(self: IA, cnv: fn@(A) -> option<B>,
blk: fn(B)) {
self.iter {|a|
alt cnv(a) {
some(b) { blk(b) }
none { }
}
}
}
fn map<A,B,IA:iterable<A>>(self: IA, cnv: fn@(A) -> B, blk: fn(B)) {
self.iter {|a|
let b = cnv(a);
@ -188,6 +198,21 @@ fn test_filter_on_uint_range() {
assert l == [0u, 2u, 4u, 6u, 8u];
}
#[test]
fn test_filter_map() {
fn negativate_the_evens(&&i: int) -> option<int> {
if i % 2 == 0 {
some(-i)
} else {
none
}
}
let l = to_list(bind filter_map(
bind int::range(0, 5, _), negativate_the_evens, _));
assert l == [0, -2, -4];
}
#[test]
fn test_flat_map_with_option() {
fn if_even(&&i: int) -> option<int> {