Parle supports regex matching similar to flex. Also supported are the following POSIX character sets: [:alnum:], [:alpha:], [:blank:], [:cntrl:], [:digit:], [:graph:], [:lower:], [:print:], [:punct:], [:space:], [:upper:] and [:xdigit:].
The Unicode character classes are currently not enabled by default, pass --enable-parle-utf32 to make them available. A particular encoding can be mapped with a correctly constructed regex. For example, to match the EURO symbol encoded in UTF-8, the regular expression [\xe2][\x82][\xac] can be used. The pattern for an UTF-8 encoded string could be [ -\x7f]{+}[\x80-\xbf]{+}[\xc2-\xdf]{+}[\xe0-\xef]{+}[\xf0-\xff]+.