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diff src/list_util.sml @ 839:b2413e4dd109

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List library additions; fix another substructure unification bug
author Adam Chlipala <adamc@hcoop.net>
date Sat, 06 Jun 2009 14:09:30 -0400
parents d20d6afc1206
children 0f7e2cca6d9b
line wrap: on
line diff
--- a/src/list_util.sml	Tue Jun 02 19:28:25 2009 -0400
+++ b/src/list_util.sml	Sat Jun 06 14:09:30 2009 -0400
@@ -136,6 +136,19 @@
         s
     end
 
+fun searchi f =
+    let
+        fun s n ls =
+            case ls of
+                [] => NONE
+              | h :: t =>
+                case f (n, h) of
+                    NONE => s (n + 1) t
+                  | v => v
+    in
+        s 0
+    end
+
 fun mapi f =
     let
         fun m i acc ls =