Mercurial > urweb
diff lib/ur/string.ur @ 2021:2da693675de9
String.trim; add OnChange to more tags
author | Adam Chlipala <adam@chlipala.net> |
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date | Tue, 10 Jun 2014 10:58:22 -0400 |
parents | 65fbb250b875 |
children | 1a4b2b983889 |
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--- a/lib/ur/string.ur Mon Jun 09 18:26:03 2014 -0400 +++ b/lib/ur/string.ur Tue Jun 10 10:58:22 2014 -0400 @@ -86,3 +86,28 @@ fun isPrefix {Full = f, Prefix = p} = length f >= length p && substring f {Start = 0, Len = length p} = p + +fun trim s = + let + val len = length s + + fun findStart i = + if i < len && Char.isSpace (sub s i) then + findStart (i+1) + else + i + + fun findFinish i = + if i >= 0 && Char.isSpace (sub s i) then + findFinish (i-1) + else + i + + val start = findStart 0 + val finish = findFinish (len - 1) + in + if finish >= start then + substring s {Start = start, Len = finish - start + 1} + else + "" + end