An attempt to escape content for a regular expression.

functions.el

(defun jeg2s-regex-escape (str)
  "Escape all special regular expression characters in the passed string."
  (if (stringp str)
      (jeg2s-regex-escape (cons "" (split-string str "" t)))
    (if (>= (safe-length str) 2)
	(if (and (not (string= "\\" (car str))) (cadr (string-match "[.*+?^$\\\\[]" str)))
	    (concat (car str) "\\" (cadr str) (jeg2s-regex-escape (cddr str)))
	  (concat (car str) (jeg2s-regex-escape (cdr str)))
      (mapconcat 'identity str "")))))