diff options
Diffstat (limited to 'lisp/emacs-lisp/regexp-opt.el')
| -rw-r--r-- | lisp/emacs-lisp/regexp-opt.el | 43 |
1 files changed, 9 insertions, 34 deletions
diff --git a/lisp/emacs-lisp/regexp-opt.el b/lisp/emacs-lisp/regexp-opt.el index 2cce4e63539..35a5fda184f 100644 --- a/lisp/emacs-lisp/regexp-opt.el +++ b/lisp/emacs-lisp/regexp-opt.el @@ -84,7 +84,7 @@ ;;; Code: ;;;###autoload -(defun regexp-opt (strings &optional paren keep-order) +(defun regexp-opt (strings &optional paren) "Return a regexp to match a string in the list STRINGS. Each member of STRINGS is treated as a fixed string, not as a regexp. Optional PAREN specifies how the returned regexp is surrounded by @@ -114,11 +114,8 @@ nil necessary to ensure that a postfix operator appended to it will apply to the whole expression. -The optional argument KEEP-ORDER, if non-nil, forces the match to -be performed in the order given, as if the strings were made into -a regexp by joining them with the `\\|' operator. If nil or -omitted, the returned regexp is will always match the longest -string possible. +The returned regexp is ordered in such a way that it will always +match the longest string possible. Up to reordering, the resulting regexp is equivalent to but usually more efficient than that of a simplified version: @@ -140,34 +137,12 @@ usually more efficient than that of a simplified version: (completion-ignore-case nil) (completion-regexp-list nil) (open (cond ((stringp paren) paren) (paren "\\("))) - (re - (cond - ;; No strings: return an unmatchable regexp. - ((null strings) - (concat (or open "\\(?:") regexp-unmatchable "\\)")) - - ;; The algorithm will generate a pattern that matches - ;; longer strings in the list before shorter. If the - ;; list order matters, then no string must come after a - ;; proper prefix of that string. To check this, verify - ;; that a straight or-pattern matches each string - ;; entirely. - ((and keep-order - (let* ((case-fold-search nil) - (alts (mapconcat #'regexp-quote strings "\\|"))) - (and (let ((s strings)) - (while (and s - (string-match alts (car s)) - (= (match-end 0) (length (car s)))) - (setq s (cdr s))) - ;; If we exited early, we found evidence that - ;; regexp-opt-group cannot be used. - s) - (concat (or open "\\(?:") alts "\\)"))))) - (t - (regexp-opt-group - (delete-dups (sort (copy-sequence strings) 'string-lessp)) - (or open t) (not open)))))) + (re (if strings + (regexp-opt-group + (delete-dups (sort (copy-sequence strings) 'string-lessp)) + (or open t) (not open)) + ;; No strings: return an unmatchable regexp. + (concat (or open "\\(?:") regexp-unmatchable "\\)")))) (cond ((eq paren 'words) (concat "\\<" re "\\>")) ((eq paren 'symbols) |