elisp - regexp-opt function missing in Emacs? -
elisp - regexp-opt function missing in Emacs? - i've started playing around elisp create font-locks (syntax highlighting) in emacs. of tutorials out there mention using elisp function "regexp-opt" optimize regular expressions, version of emacs (23.2) doesn't seem have function. furthermore, googling reply doesn't seem turn useful results. ideas? as can find out via c-h f regexp-opt : regexp-opt compiled lisp function. (regexp-opt strings &optional paren) return regexp match string in list strings. each string should unique in strings , should not contain regexps, quoted or not. if optional paren non-nil, ensure returned regexp enclosed @ to the lowest degree 1 regexp grouping construct. returned regexp typically more efficient equivalent regexp: (let ((open (if paren "\(" "")) (close (if paren "\)" ""))) (concat open (mapconcat 'regexp-quote strings ...