diff options
Diffstat (limited to 'lib/ur/string.ur')
| -rw-r--r-- | lib/ur/string.ur | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/lib/ur/string.ur b/lib/ur/string.ur index f19ce174..f7781e01 100644 --- a/lib/ur/string.ur +++ b/lib/ur/string.ur @@ -11,7 +11,15 @@ val suffix = Basis.strsuffix val index = Basis.strindex val atFirst = Basis.strchr -fun mindex {Haystack = s, Needle = chs} = Basis.strcspn s chs +fun mindex {Haystack = s, Needle = chs} = + let + val n = Basis.strcspn s chs + in + if n >= length s then + None + else + Some n + end fun substring s {Start = start, Len = len} = Basis.substring s start len |