;;; tildify.el --- adding hard spaces into texts -*- lexical-binding: t -*-
-;; Copyright (C) 1997-2014 Free Software Foundation, Inc.
+;; Copyright (C) 1997-2015 Free Software Foundation, Inc.
;; Author: Milan Zamazal <pdm@zamazal.org>
;; Michal Nazarewicz <mina86@mina86.com>
-;; Version: 4.5.7
+;; Version: 4.6.1
;; Keywords: text, TeX, SGML, wp
;; This file is part of GNU Emacs.
(t t))))))
+;;; *** Tildify Mode ***
+
+(defcustom tildify-space-pattern "[,:;(][ \t]*[a]\\|\\<[AIKOSUVWZikosuvwz]"
+ "Pattern specifying whether to insert a hard space at point.
+
+If the pattern matches `looking-back', a hard space needs to be inserted instead
+of a space at point. The regexp is always case sensitive, regardless of the
+current `case-fold-search' setting."
+ :version "25.1"
+ :group 'tildify
+ :type 'string)
+
+(defcustom tildify-space-predicates '(tildify-space-region-predicate)
+ "A list of predicate functions for `tildify-space' function."
+ :version "25.1"
+ :group 'tildify
+ :type '(repeat 'function))
+
+(defcustom tildify-double-space-undos t
+ "Weather `tildify-space' should undo hard space when space is typed again."
+ :version "25.1"
+ :group 'tildify
+ :type 'boolean)
+
+;;;###autoload
+(defun tildify-space ()
+ "Convert space before point into a hard space if the context is right.
+
+If
+ * character before point is a space character,
+ * character before that has “w” character syntax (i.e. it's a word
+ constituent),
+ * `tildify-space-pattern' matches when `looking-back' (no more than 10
+ characters) from before the space character, and
+ * all predicates in `tildify-space-predicates' return non-nil,
+replace the space character with value of `tildify-space-string' and
+return t.
+
+Otherwise, if
+ * `tildify-double-space-undos' variable is non-nil,
+ * character before point is a space character, and
+ * text before that is a hard space as defined by
+ `tildify-space-string' variable,
+remove the hard space and leave only the space character.
+
+This function is meant to be used as a `post-self-insert-hook'."
+ (interactive)
+ (let* ((p (point)) (p-1 (1- p)) (n (- p (point-min)))
+ (l (length tildify-space-string)) (l+1 (1+ l))
+ case-fold-search)
+ (when (and (> n 2) (eq (preceding-char) ?\s))
+ (cond
+ ((and (eq (char-syntax (char-before p-1)) ?w)
+ (save-excursion
+ (goto-char p-1)
+ (looking-back tildify-space-pattern (max (point-min) (- p 10))))
+ (run-hook-with-args-until-failure 'tildify-space-predicates))
+ (delete-char -1)
+ (insert tildify-space-string)
+ t)
+ ((and tildify-double-space-undos
+ (> n l+1)
+ (string-equal tildify-space-string
+ (buffer-substring (- p l+1) p-1)))
+ (goto-char p-1)
+ (delete-char (- l))
+ (goto-char (1+ (point)))
+ nil)))))
+
+(defun tildify-space-region-predicate ()
+ "Check whether character before point should be tildified.
+Based on `tildify-foreach-region-function', check whether character before,
+which is assumed to be a space character, should be replaced with a hard space."
+ (catch 'found
+ (tildify--foreach-region (lambda (_b _e) (throw 'found t)) (1- (point)) (point))))
+
+;;;###autoload
+(define-minor-mode tildify-mode
+ "Adds electric behaviour to space character.
+
+When space is inserted into a buffer in a position where hard space is required
+instead (determined by `tildify-space-pattern' and `tildify-space-predicates'),
+that space character is replaced by a hard space specified by
+`tildify-space-string'. Converting of the space is done by `tildify-space'.
+
+When `tildify-mode' is enabled, if `tildify-string-alist' specifies a hard space
+representation for current major mode, the `tildify-space-string' buffer-local
+variable will be set to the representation."
+ nil " ~" nil
+ (when tildify-mode
+ (let ((space (tildify--pick-alist-entry tildify-string-alist)))
+ (if (not (string-equal " " (or space tildify-space-string)))
+ (when space
+ (setq tildify-space-string space))
+ (message (eval-when-compile
+ (concat "Hard space is a single space character, tildify-"
+ "mode won't have any effect, disabling.")))
+ (setq tildify-mode nil))))
+ (if tildify-mode
+ (add-hook 'post-self-insert-hook 'tildify-space nil t)
+ (remove-hook 'post-self-insert-hook 'tildify-space t)))
+
+
;;; *** Announce ***
(provide 'tildify)