--- /dev/null
+;;; auto-overlay-line.el --- automatic overlays for single lines
+
+
+;; Copyright (C) 2005-2015 Free Software Foundation, Inc
+
+;; Author: Toby Cubitt <toby-predictive@dr-qubit.org>
+;; Maintainer: Toby Cubitt <toby-predictive@dr-qubit.org>
+;; URL: http://www.dr-qubit.org/emacs.php
+;; Repository: http://www.dr-qubit.org/git/predictive.git
+
+;; This file is part of the Emacs.
+;;
+;; This file is free software: you can redistribute it and/or modify it under
+;; the terms of the GNU General Public License as published by the Free
+;; Software Foundation, either version 3 of the License, or (at your option)
+;; any later version.
+;;
+;; This program is distributed in the hope that it will be useful, but WITHOUT
+;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+;; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+;; more details.
+;;
+;; You should have received a copy of the GNU General Public License along
+;; with this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+;;; Code:
+
+(require 'auto-overlays)
+(provide 'auto-overlay-line)
+
+
+;; set line overlay parsing and suicide funtions
+(put 'line 'auto-overlay-parse-function 'auto-o-parse-line-match)
+(put 'line 'auto-overlay-suicide-function
+ (lambda (o) (auto-o-delete-overlay (overlay-get o 'parent))))
+
+
+
+(defun auto-o-parse-line-match (o-match)
+ ;; Create overlay for a new line match.
+ (let ((o-new (make-overlay (overlay-get o-match 'delim-end)
+ (save-excursion
+ (goto-char (overlay-get o-match 'delim-end))
+ (1+ (line-end-position))))))
+
+ ;; give new overlay some basic properties
+ (overlay-put o-new 'auto-overlay t)
+ (overlay-put o-new 'set-id (overlay-get o-match 'set-id))
+ (overlay-put o-new 'definition-id (overlay-get o-match 'definition-id))
+ ;; match start of new overlay with match
+ (auto-o-match-overlay o-new o-match nil)
+ ;; set overlay's modification hooks to ensure that it always extends to
+ ;; end of line
+ (overlay-put o-new 'modification-hooks
+ (cons 'auto-o-schedule-extend-line
+ (overlay-get o-new 'modification-hooks)))
+ ;; return new overlay
+ o-new))
+
+
+(defun auto-o-schedule-extend-line (o-self modified &rest unused)
+ ;; All line overlay modification hooks are set to this function, which
+ ;; schedules `auto-o-extend-line' to run after any suicide functions have
+ ;; been called, but before the overlays are updated.
+ (unless modified
+ (push (list 'auto-o-extend-line o-self) auto-o-pending-post-suicide)))
+
+
+
+(defun auto-o-extend-line (o-self)
+ ;; Checks if overlay still extends to end of line, and update the necessary
+ ;; if not.
+
+ ;; if we haven't been deleted by a suicide function...
+ (when (overlay-buffer o-self)
+ (save-match-data
+ (let ((start (overlay-start o-self))
+ (end (overlay-end o-self)))
+ (cond
+ ;; if we no longer extend to end of line...
+ ((null (string-match "\n" (buffer-substring-no-properties
+ (overlay-start o-self)
+ (overlay-end o-self))))
+ ;; grow ourselves so we extend till end of line
+ (move-overlay o-self start (save-excursion
+ (goto-char (overlay-end o-self))
+ (1+ (line-end-position))))
+ ;; if we're exclusive, delete lower priority overlays in newly
+ ;; covered region
+ (auto-o-update-exclusive (overlay-get o-self 'set-id)
+ end (overlay-end o-self)
+ nil (overlay-get o-self 'priority)))
+
+ ;; if we extend beyond end of line...
+ ((/= (overlay-end o-self) (+ start (match-end 0)))
+ ;; shrink ourselves so we extend till end of line
+ (move-overlay o-self start (+ start (match-end 0)))
+ ;; if we're exclusive, re-parse region that is no longer covered
+ (auto-o-update-exclusive (overlay-get o-self 'set-id)
+ (overlay-end o-self) end
+ (overlay-get o-self 'priority) nil))
+ )))))
+
+
+;; auto-overlay-line.el ends here