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230 lines
8.0 KiB
EmacsLisp
230 lines
8.0 KiB
EmacsLisp
;;; paren.el --- highlight matching paren.
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;; Copyright (C) 1993, 1996 Free Software Foundation, Inc.
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;; Author: rms@gnu.org
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;; Maintainer: FSF
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;; Keywords: languages, faces
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to the
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;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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;; Boston, MA 02111-1307, USA.
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;;; Commentary:
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;; Load this and it will display highlighting on whatever
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;; paren matches the one before or after point.
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;;; Code:
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(defgroup paren-showing nil
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"Showing (un)matching of parens and expressions."
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:prefix "show-paren-"
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:group 'paren-matching)
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;; This is the overlay used to highlight the matching paren.
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(defvar show-paren-overlay nil)
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;; This is the overlay used to highlight the closeparen right before point.
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(defvar show-paren-overlay-1 nil)
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(defcustom show-paren-style 'parenthesis
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"*Style used when showing a matching paren.
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Valid styles are `parenthesis' (meaning show the matching paren),
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`expression' (meaning show the entire expression enclosed by the paren) and
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`mixed' (meaning show the matching paren if it is visible, and the expression
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otherwise)."
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:type '(choice (const parenthesis) (const expression) (const mixed))
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:group 'paren-showing)
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(defcustom show-paren-delay
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(if (featurep 'lisp-float-type) (/ (float 1) (float 8)) 1)
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"*Time in seconds to delay before showing a matching paren."
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:type '(number :tag "seconds")
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:group 'paren-showing)
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(defcustom show-paren-priority 1000
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"*Priority of paren highlighting overlays."
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:type 'integer
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:group 'paren-showing
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:version "21.1")
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(defcustom show-paren-ring-bell-on-mismatch nil
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"*If non-nil, beep if mismatched paren is detected."
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:type 'boolean
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:group 'paren-showing
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:version "20.3")
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(defface show-paren-match-face
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'((((class color)) (:background "turquoise"))
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(t (:background "gray")))
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"Show Paren mode face used for a matching paren."
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:group 'faces
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:group 'paren-showing)
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(defface show-paren-mismatch-face
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'((((class color)) (:foreground "white" :background "purple"))
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(t (:reverse-video t)))
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"Show Paren mode face used for a mismatching paren."
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:group 'faces
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:group 'paren-showing)
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(defvar show-paren-idle-timer nil)
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;;;###autoload
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(define-minor-mode show-paren-mode
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"Toggle Show Paren mode.
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With prefix ARG, turn Show Paren mode on if and only if ARG is positive.
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Returns the new status of Show Paren mode (non-nil means on).
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When Show Paren mode is enabled, any matching parenthesis is highlighted
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in `show-paren-style' after `show-paren-delay' seconds of Emacs idle time."
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:global t :group 'paren-showing
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;; Turn off the usual paren-matching method
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;; when this one is turned on.
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(if (local-variable-p 'show-paren-mode)
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(make-local-variable 'blink-matching-paren-on-screen)
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(kill-local-variable 'blink-matching-paren-on-screen))
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(setq blink-matching-paren-on-screen (not show-paren-mode))
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;; Now enable or disable the mechanism.
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;; First get rid of the old idle timer.
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(if show-paren-idle-timer
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(cancel-timer show-paren-idle-timer))
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(setq show-paren-idle-timer nil)
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;; If show-paren-mode is enabled in some buffer now,
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;; set up a new timer.
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(when (memq t (mapcar (lambda (buffer)
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(with-current-buffer buffer
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show-paren-mode))
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(buffer-list)))
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(setq show-paren-idle-timer (run-with-idle-timer
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show-paren-delay t
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'show-paren-function)))
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(unless show-paren-mode
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(and show-paren-overlay
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(eq (overlay-buffer show-paren-overlay) (current-buffer))
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(delete-overlay show-paren-overlay))
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(and show-paren-overlay-1
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(eq (overlay-buffer show-paren-overlay-1) (current-buffer))
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(delete-overlay show-paren-overlay-1))))
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;; Find the place to show, if there is one,
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;; and show it until input arrives.
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(defun show-paren-function ()
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(if show-paren-mode
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(let (pos dir mismatch face (oldpos (point)))
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(cond ((eq (char-syntax (preceding-char)) ?\))
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(setq dir -1))
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((eq (char-syntax (following-char)) ?\()
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(setq dir 1)))
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;;
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;; Find the other end of the sexp.
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(when dir
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(save-excursion
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(save-restriction
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;; Determine the range within which to look for a match.
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(when blink-matching-paren-distance
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(narrow-to-region
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(max (point-min) (- (point) blink-matching-paren-distance))
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(min (point-max) (+ (point) blink-matching-paren-distance))))
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;; Scan across one sexp within that range.
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;; Errors or nil mean there is a mismatch.
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(condition-case ()
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(setq pos (scan-sexps (point) dir))
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(error (setq pos t mismatch t)))
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;; If found a "matching" paren, see if it is the right
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;; kind of paren to match the one we started at.
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(when (integerp pos)
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(let ((beg (min pos oldpos)) (end (max pos oldpos)))
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(when (/= (char-syntax (char-after beg)) ?\$)
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(setq mismatch
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(not (eq (char-before end)
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;; This can give nil.
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(matching-paren (char-after beg)))))))))))
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;;
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;; Highlight the other end of the sexp, or unhighlight if none.
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(if (not pos)
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(progn
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;; If not at a paren that has a match,
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;; turn off any previous paren highlighting.
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(and show-paren-overlay (overlay-buffer show-paren-overlay)
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(delete-overlay show-paren-overlay))
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(and show-paren-overlay-1 (overlay-buffer show-paren-overlay-1)
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(delete-overlay show-paren-overlay-1)))
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;;
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;; Use the correct face.
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(if mismatch
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(progn
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(if show-paren-ring-bell-on-mismatch
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(beep))
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(setq face 'show-paren-mismatch-face))
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(setq face 'show-paren-match-face))
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;;
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;; If matching backwards, highlight the closeparen
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;; before point as well as its matching open.
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;; If matching forward, and the openparen is unbalanced,
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;; highlight the paren at point to indicate misbalance.
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;; Otherwise, turn off any such highlighting.
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(if (and (= dir 1) (integerp pos))
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(when (and show-paren-overlay-1
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(overlay-buffer show-paren-overlay-1))
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(delete-overlay show-paren-overlay-1))
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(let ((from (if (= dir 1)
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(point)
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(forward-point -1)))
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(to (if (= dir 1)
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(forward-point 1)
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(point))))
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(if show-paren-overlay-1
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(move-overlay show-paren-overlay-1 from to (current-buffer))
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(setq show-paren-overlay-1 (make-overlay from to)))
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;; Always set the overlay face, since it varies.
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(overlay-put show-paren-overlay-1 'priority show-paren-priority)
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(overlay-put show-paren-overlay-1 'face face)))
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;;
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;; Turn on highlighting for the matching paren, if found.
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;; If it's an unmatched paren, turn off any such highlighting.
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(unless (integerp pos)
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(delete-overlay show-paren-overlay))
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(let ((to (if (or (eq show-paren-style 'expression)
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(and (eq show-paren-style 'mixed)
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(not (pos-visible-in-window-p pos))))
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(point)
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pos))
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(from (if (or (eq show-paren-style 'expression)
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(and (eq show-paren-style 'mixed)
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(not (pos-visible-in-window-p pos))))
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pos
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(save-excursion
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(goto-char pos)
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(forward-point (- dir))))))
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(if show-paren-overlay
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(move-overlay show-paren-overlay from to (current-buffer))
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(setq show-paren-overlay (make-overlay from to))))
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;;
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;; Always set the overlay face, since it varies.
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(overlay-put show-paren-overlay 'priority show-paren-priority)
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(overlay-put show-paren-overlay 'face face)))
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;; show-paren-mode is nil in this buffer.
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(and show-paren-overlay
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(delete-overlay show-paren-overlay))
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(and show-paren-overlay-1
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(delete-overlay show-paren-overlay-1))))
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(provide 'paren)
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;;; paren.el ends here
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