-;;; regexp-opt.el --- generate efficient regexps to match strings.
+;;; regexp-opt.el --- generate efficient regexps to match strings
-;; Copyright (C) 1994,95,96,97,98,99,2000 Free Software Foundation, Inc.
+;; Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2002,
+;; 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
;; Author: Simon Marshall <simon@gnu.org>
;; Maintainer: FSF
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING. If not, write to the
-;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-;; Boston, MA 02111-1307, USA.
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
;;; Commentary:
is enclosed by at least one regexp grouping construct.
The returned regexp is typically more efficient than the equivalent regexp:
- (let ((open-paren (if PAREN \"\\\\(\" \"\")) (close-paren (if PAREN \"\\\\)\" \"\")))
- (concat open-paren (mapconcat 'regexp-quote STRINGS \"\\\\|\") close-paren))"
+ (let ((open (if PAREN \"\\\\(\" \"\")) (close (if PAREN \"\\\\)\" \"\")))
+ (concat open (mapconcat 'regexp-quote STRINGS \"\\\\|\") close))
+
+If PAREN is `words', then the resulting regexp is additionally surrounded
+by \\=\\< and \\>."
(save-match-data
;; Recurse on the sorted list.
- (let ((max-lisp-eval-depth (* 1024 1024))
- (completion-ignore-case nil))
- (setq paren (cond ((stringp paren) paren) (paren "\\(")))
- (regexp-opt-group (sort (copy-sequence strings) 'string-lessp) paren))))
+ (let* ((max-lisp-eval-depth (* 1024 1024))
+ (max-specpdl-size (* 1024 1024))
+ (completion-ignore-case nil)
+ (completion-regexp-list nil)
+ (words (eq paren 'words))
+ (open (cond ((stringp paren) paren) (paren "\\(")))
+ (sorted-strings (delete-dups
+ (sort (copy-sequence strings) 'string-lessp)))
+ (re (regexp-opt-group sorted-strings open)))
+ (if words (concat "\\<" re "\\>") re))))
;;;###autoload
(defun regexp-opt-depth (regexp)
"Return the depth of REGEXP.
-This means the number of regexp grouping constructs (parenthesised expressions)
-in REGEXP."
+This means the number of non-shy regexp grouping constructs
+\(parenthesized expressions) in REGEXP."
(save-match-data
;; Hack to signal an error if REGEXP does not have balanced parentheses.
(string-match regexp "")
;; Count the number of open parentheses in REGEXP.
- (let ((count 0) start)
- (while (string-match "\\(\\`\\|[^\\]\\)\\\\\\(\\\\\\\\\\)*([^?]"
- regexp start)
- (setq count (1+ count) start (match-end 0)))
+ (let ((count 0) start last)
+ (while (string-match "\\\\(\\(\\?:\\)?" regexp start)
+ (setq start (match-end 0)) ; Start of next search.
+ (when (and (not (match-beginning 1))
+ (subregexp-context-p regexp (match-beginning 0) last))
+ ;; It's not a shy group and it's not inside brackets or after
+ ;; a backslash: it's really a group-open marker.
+ (setq last start) ; Speed up next regexp-opt-re-context-p.
+ (setq count (1+ count))))
count)))
\f
;;; Workhorse functions.
(require 'cl))
(defun regexp-opt-group (strings &optional paren lax)
- "Return a regexp to match a string in STRINGS.
-If PAREN non-nil, output regexp parentheses around returned regexp.
-If LAX non-nil, don't output parentheses if it doesn't require them.
-Merges keywords to avoid backtracking in Emacs' regexp matcher.
+ ;; Return a regexp to match a string in the sorted list STRINGS.
+ ;; If PAREN non-nil, output regexp parentheses around returned regexp.
+ ;; If LAX non-nil, don't output parentheses if it doesn't require them.
+ ;; Merges keywords to avoid backtracking in Emacs' regexp matcher.
-The basic idea is to find the shortest common prefix or suffix, remove it
-and recurse. If there is no prefix, we divide the list into two so that
-\(at least) one half will have at least a one-character common prefix.
+ ;; The basic idea is to find the shortest common prefix or suffix, remove it
+ ;; and recurse. If there is no prefix, we divide the list into two so that
+ ;; \(at least) one half will have at least a one-character common prefix.
-Also we delay the addition of grouping parenthesis as long as possible
-until we're sure we need them, and try to remove one-character sequences
-so we can use character sets rather than grouping parenthesis."
+ ;; Also we delay the addition of grouping parenthesis as long as possible
+ ;; until we're sure we need them, and try to remove one-character sequences
+ ;; so we can use character sets rather than grouping parenthesis.
(let* ((open-group (cond ((stringp paren) paren) (paren "\\(?:") (t "")))
(close-group (if paren "\\)" ""))
(open-charset (if lax "" open-group))
;;
;; We have a list of different length strings.
(t
- (let ((prefix (try-completion "" (mapcar 'list strings))))
+ (let ((prefix (try-completion "" strings)))
(if (> (length prefix) 0)
;; common prefix: take it and recurse on the suffixes.
(let* ((n (length prefix))
(suffixes (mapcar (lambda (s) (substring s n)) strings)))
- (concat open-charset
+ (concat open-group
(regexp-quote prefix)
(regexp-opt-group suffixes t t)
- close-charset))
+ close-group))
(let* ((sgnirts (mapcar (lambda (s)
(concat (nreverse (string-to-list s))))
strings))
- (xiffus (try-completion "" (mapcar 'list sgnirts))))
+ (xiffus (try-completion "" sgnirts)))
(if (> (length xiffus) 0)
;; common suffix: take it and recurse on the prefixes.
(let* ((n (- (length xiffus)))
- (prefixes (mapcar (lambda (s) (substring s 0 n)) strings)))
- (concat open-charset
+ (prefixes
+ ;; Sorting is necessary in cases such as ("ad" "d").
+ (sort (mapcar (lambda (s) (substring s 0 n)) strings)
+ 'string-lessp)))
+ (concat open-group
(regexp-opt-group prefixes t t)
(regexp-quote
(concat (nreverse (string-to-list xiffus))))
- close-charset))
-
+ close-group))
+
;; Otherwise, divide the list into those that start with a
;; particular letter and those that do not, and recurse on them.
(let* ((char (char-to-string (string-to-char (car strings))))
- (half1 (all-completions char (mapcar 'list strings)))
+ (half1 (all-completions char strings))
(half2 (nthcdr (length half1) strings)))
(concat open-group
(regexp-opt-group half1)
(provide 'regexp-opt)
+;; arch-tag: 6c5a66f4-29af-4fd6-8c3b-4b554d5b4370
;;; regexp-opt.el ends here