[dasyatidprime]

Emacs users have used regexp-opt in their own syntax highlighting (aka font-lock) for a while now, at least. If you wanted to port it, it'd depend on whether you're okay with the license, presumably, though I don't think writing a simple version from scratch would be that hard. (Do not let your eyes jump to the source block in the manual and then assume that it's not what you asked: that example is specifically described as the inefficient equivalent.) http://www.gnu.org/software/emacs/manual/html_node/elisp/Reg...