std.string inPattern() and UTF symbols

[Fra]

various (UTF) symbols seems to be ignored by inPattern, see 
http://dpaste.dzfl.pl/e8ff9002 for a quick example (munch() uses 
inPattern() internally)

Is it me doing something in an improper way, or is the 
documentation lacking more specific limitation of the function? 
All I can read is "In the future, the pattern syntax may be 
improved to be more like regular expression character classes". 
This doesn't sound like "non-ascii symbols are not supported"