diff options
Diffstat (limited to 'src/test/ui/array-slice-vec/vec-matching-fold.rs')
-rw-r--r-- | src/test/ui/array-slice-vec/vec-matching-fold.rs | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/src/test/ui/array-slice-vec/vec-matching-fold.rs b/src/test/ui/array-slice-vec/vec-matching-fold.rs new file mode 100644 index 000000000..998899271 --- /dev/null +++ b/src/test/ui/array-slice-vec/vec-matching-fold.rs @@ -0,0 +1,46 @@ +// run-pass + +use std::fmt::Debug; + +fn foldl<T, U, F>(values: &[T], + initial: U, + mut function: F) + -> U where + U: Clone+Debug, T:Debug, + F: FnMut(U, &T) -> U, +{ match values { + &[ref head, ref tail @ ..] => + foldl(tail, function(initial, head), function), + &[] => { + // FIXME: call guards + let res = initial.clone(); res + } + } +} + +fn foldr<T, U, F>(values: &[T], + initial: U, + mut function: F) + -> U where + U: Clone, + F: FnMut(&T, U) -> U, +{ + match values { + &[ref head @ .., ref tail] => + foldr(head, function(tail, initial), function), + &[] => { + // FIXME: call guards + let res = initial.clone(); res + } + } +} + +pub fn main() { + let x = &[1, 2, 3, 4, 5]; + + let product = foldl(x, 1, |a, b| a * *b); + assert_eq!(product, 120); + + let sum = foldr(x, 0, |a, b| *a + b); + assert_eq!(sum, 15); +} |