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Import looking-back from GNU Emacs. -------------------- ChangeLog entries follow: -------------------- lisp/ChangeLog addition: 2011-04-30 Didier Verna <didier@xemacs.org> * subr.el (looking-back): New function.
author Didier Verna <didier@lrde.epita.fr>
date Sat, 30 Apr 2011 17:38:35 +0200
parents ac37a5f7e5be
children d3e0482c7899
comparison
equal deleted inserted replaced
5487:dc37764a105b 5488:1e544fd7be12
729 (substring string (match-beginning num) (match-end num)))) 729 (substring string (match-beginning num) (match-end num))))
730 (set-text-properties 0 (length result) nil result) 730 (set-text-properties 0 (length result) nil result)
731 result) 731 result)
732 (buffer-substring-no-properties (match-beginning num) 732 (buffer-substring-no-properties (match-beginning num)
733 (match-end num))))) 733 (match-end num)))))
734
735 ;; Imported from GNU Emacs 23.3.1 -- dvl
736 (defun looking-back (regexp &optional limit greedy)
737 "Return non-nil if text before point matches regular expression REGEXP.
738 Like `looking-at' except matches before point, and is slower.
739 LIMIT if non-nil speeds up the search by specifying a minimum
740 starting position, to avoid checking matches that would start
741 before LIMIT.
742
743 If GREEDY is non-nil, extend the match backwards as far as
744 possible, stopping when a single additional previous character
745 cannot be part of a match for REGEXP. When the match is
746 extended, its starting position is allowed to occur before
747 LIMIT."
748 (let ((start (point))
749 (pos
750 (save-excursion
751 (and (re-search-backward (concat "\\(?:" regexp "\\)\\=") limit t)
752 (point)))))
753 (if (and greedy pos)
754 (save-restriction
755 (narrow-to-region (point-min) start)
756 (while (and (> pos (point-min))
757 (save-excursion
758 (goto-char pos)
759 (backward-char 1)
760 (looking-at (concat "\\(?:" regexp "\\)\\'"))))
761 (setq pos (1- pos)))
762 (save-excursion
763 (goto-char pos)
764 (looking-at (concat "\\(?:" regexp "\\)\\'")))))
765 (not (null pos))))
734 766
735 (defconst split-string-default-separators "[ \f\t\n\r\v]+" 767 (defconst split-string-default-separators "[ \f\t\n\r\v]+"
736 "The default value of separators for `split-string'. 768 "The default value of separators for `split-string'.
737 769
738 A regexp matching strings of whitespace. May be locale-dependent 770 A regexp matching strings of whitespace. May be locale-dependent