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author | Adam Chlipala <adam@chlipala.net> | 2011-07-24 15:47:09 -0400 |
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committer | Adam Chlipala <adam@chlipala.net> | 2011-07-24 15:47:09 -0400 |
commit | 729998f64e891856f43f758551be0aaa26ac89b4 (patch) | |
tree | 1eca16f08da61d48e50376918cdf6b1c4b0acb81 | |
parent | 2bf2fd370971509c6a00fb7000d9c2aa28852719 (diff) |
List.find
-rw-r--r-- | lib/ur/list.ur | 14 | ||||
-rw-r--r-- | lib/ur/list.urs | 2 |
2 files changed, 16 insertions, 0 deletions
diff --git a/lib/ur/list.ur b/lib/ur/list.ur index 32a9679c..2679d877 100644 --- a/lib/ur/list.ur +++ b/lib/ur/list.ur @@ -206,6 +206,20 @@ fun foldlMap [a] [b] [c] f = fold [] end +fun find [a] f = + let + fun find' ls = + case ls of + [] => None + | x :: ls => + if f x then + Some x + else + find' ls + in + find' + end + fun search [a] [b] f = let fun search' ls = diff --git a/lib/ur/list.urs b/lib/ur/list.urs index dc8fdeba..00bb5b48 100644 --- a/lib/ur/list.urs +++ b/lib/ur/list.urs @@ -44,6 +44,8 @@ val foldlM : m ::: (Type -> Type) -> monad m -> a ::: Type -> b ::: Type val foldlMap : a ::: Type -> b ::: Type -> c ::: Type -> (a -> b -> c * b) -> b -> t a -> t c * b +val find : a ::: Type -> (a -> bool) -> t a -> option a + val search : a ::: Type -> b ::: Type -> (a -> option b) -> t a -> option b val all : a ::: Type -> (a -> bool) -> t a -> bool |