# HG changeset patch
# User Adam Chlipala <adam@chlipala.net>
# Date 1311536829 14400
# Node ID ada582d07ae1c926447a799cb7b7de3c028f9d2d
# Parent  883347f5c3c20bf4c47c24f59fb87f3b03523b1c
List.find

diff -r 883347f5c3c2 -r ada582d07ae1 lib/ur/list.ur
--- a/lib/ur/list.ur	Sun Jul 24 14:49:40 2011 -0400
+++ b/lib/ur/list.ur	Sun Jul 24 15:47:09 2011 -0400
@@ -206,6 +206,20 @@
         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 -r 883347f5c3c2 -r ada582d07ae1 lib/ur/list.urs
--- a/lib/ur/list.urs	Sun Jul 24 14:49:40 2011 -0400
+++ b/lib/ur/list.urs	Sun Jul 24 15:47:09 2011 -0400
@@ -44,6 +44,8 @@
 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