Full regular expression support, using boost::regex. The patch includes a batch file to build neatly build the bits of boost that need building, and actually only adds a single line to the scintilla makefile (scintilla.mak).
Simply unpack boost from the standard download (from www.boost.org), and run
Then build scintilla as normal with the standard nmake -f scintilla.mak
The N++ modifications are only to cope with identifying an invalid regular expression, rather than simply saying "not found".
Based on the work of Simon Steele for Programmer's Notepad 2 - although this is converted to use boost::regex instead of boost::xpressive.
It's a tad quicker than the built-in reg-ex, and supports all modern regular expression operators, including back-references and multi-line searching. Named groups are also supported, and can be used in the "replace" string.
Based on revision 860, although the scintilla part should be fine a long way back as it only adds a single line.