mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Add get_opt to std::vec

Browse Source
This commit is contained in:
Harry Marr 2013-09-29 16:59:00 +01:00
parent 9883a6250b
commit 21b24e148b
1 changed files with 18 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
src/libstd/vec.rs
View File

@ -840,6 +840,7 @@ pub trait ImmutableVector<'self, T> {
fn window_iter(self, size: uint) -> WindowIter<'self, T>;
fn chunk_iter(self, size: uint) -> ChunkIter<'self, T>;
fn get_opt(&self, index: uint) -> Option<&'self T>;
fn head(&self) -> &'self T;
fn head_opt(&self) -> Option<&'self T>;
fn tail(&self) -> &'self [T];
@ -1019,6 +1020,13 @@ impl<'self,T> ImmutableVector<'self, T> for &'self [T] {
ChunkIter { v: self, size: size }
}
/// Returns the element of a vector at the given index, or `None` if the
/// index is out of bounds
#[inline]
fn get_opt(&self, index: uint) -> Option<&'self T> {
if index < self.len() { Some(&self[index]) } else { None }
}
/// Returns the first element of a vector, failing if the vector is empty.
#[inline]
fn head(&self) -> &'self T {
@ -2574,6 +2582,16 @@ mod tests {
assert_eq!(v2.len(), 2);
}
#[test]
fn test_get_opt() {
let mut a = ~[11];
assert_eq!(a.get_opt(1), None);
a = ~[11, 12];
assert_eq!(a.get_opt(1).unwrap(), &12);
a = ~[11, 12, 13];
assert_eq!(a.get_opt(1).unwrap(), &12);
}
#[test]
fn test_head() {
let mut a = ~[11];