devel/libagcre - The NetBSD Packages Collection

The resulting library is libagcre, which implements regular expression
compilation and execution. It uses the Pike Virtual Machine approach:

+ standard POSIX features where sane
+ some/most Perl escapes
+ lazy matching via '?'
+ non-capture parentheses (?:...)
+ in-expression case-insensitive directives are supported (?i)...(?-i)
+ all case-insensitivity is actioned at expression exec time.
+ utf-8 is supported both for expressions and for input text when
  matching
+ unicode escapes (in the Java format of \uABCD) are supported
+ wide character support is also provided. Expressions can be compiled
  in utf-8, and searched using wchar_t arrays. When matching, start and
  end offsets are given relative to the input format: utf-8 is a byte
  offset from the start of the stream, and wide chars are given in
  wide character offsets from the start
+ exact multiple repetition specifiers {N}, and {N,M} are supported
+ backreferences are supported
+ at the most basic level, individual 32bit unicode characters are
  matched
+ an egrep/grep implementation for matching unicode regexps included