Emacs Lisp 正则表达式简化

r.el

(defun conj (v &rest c)
  (append v c))

(defun r (exp)
  (do ((e (cons nil (string-to-list exp))
          (let ((s (car e)) (x (cdr e))
                (a (cadr e)) (d (caddr e)))
            (cond
             ((= a ?%)
              (cons (apply (apply-partially #'conj s)
                           (conj (if (memq d (string-to-list "[wbsc]"))
                                   (list ?\\))
                                 d))
                    (nthcdr 2 x)))
             ((memq a (string-to-list "(){}|"))
              (cons (conj s ?\\ a) (cdr x)))
             (t (cons (conj s a) (cdr x)))))))
      ((null (cdr e)) (apply #'string (car e)))))

(r "(a|b){2,3}%%%(x%)%{%} %w %b %s- %cl abcd%%")
; => "(a|b){2,3}%(x){} \w \b \s- \cl abcd%"
还需要考虑[]中的特殊字符将变成普通字符