changeset 1174:9df124fcab3d

String.isPrefix
author Adam Chlipala <adamc@hcoop.net>
date Tue, 02 Mar 2010 09:46:17 -0500
parents 983d9b38abc7
children 79f487f51d9f
files lib/ur/string.ur lib/ur/string.urs
diffstat 2 files changed, 5 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- a/lib/ur/string.ur	Sun Feb 28 15:46:41 2010 -0500
+++ b/lib/ur/string.ur	Tue Mar 02 09:46:17 2010 -0500
@@ -53,3 +53,6 @@
     case split s #"\n" of
         None => cdata s
       | Some (s1, s2) => <xml>{[s1]}<br/>{newlines s2}</xml>
+
+fun isPrefix {Full = f, Prefix = p} =
+    length f >= length p && substring f {Start = 0, Len = length p} = p
--- a/lib/ur/string.urs	Sun Feb 28 15:46:41 2010 -0500
+++ b/lib/ur/string.urs	Tue Mar 02 09:46:17 2010 -0500
@@ -23,3 +23,5 @@
 val mp : (char -> char) -> string -> string
 
 val newlines : ctx ::: {Unit} -> [[Body] ~ ctx] => string -> xml ([Body] ++ ctx) [] []
+
+val isPrefix : {Full : t, Prefix : t} -> bool