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;; sym-lock.el - Extension of Font-Lock mode for symbol fontification.

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;;        Copyright © 1997-1998 Albert Cohen, all rights reserved.
;;         Copying is covered by the GNU General Public License.
;;
;;    This program 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 2 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.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;                                 History
;; 
;; first prototype by wg <wg@cs.tu-berlin.de> 5-96
;; tweaked by Steve Dunham <dunham@gdl.msu.edu> 5-96
;; rewritten and enhanced by Albert Cohen <Albert.Cohen@prism.uvsq.fr> 3-97
;; new symbol-face format and ergonomy improvement by Albert Cohen 2-98
;; major step towards portability and customization by Albert Cohen 5-98
;; removed bug with multiple appends in hook by Albert Cohen 3-99
;; removed sym-lock-face&atom which where not working by C Raffalli 4-2000 

;; more about symbol font ? check out: xfd -fn '-adobe-symbol-*--12-*'

(require 'font-lock)
(require 'atomic-extents)

(defvar sym-lock-sym-count 0
  "Counter for internal symbols.")

(defvar sym-lock-ext-start nil "Temporary for atomicization.")
(make-variable-buffer-local 'sym-lock-ext-start)
(defvar sym-lock-ext-end nil "Temporary for atomicization.")
(make-variable-buffer-local 'sym-lock-ext-end)

(defvar sym-lock-font-size nil
  "Default size for Sym-Lock symbol font.")
(make-variable-buffer-local 'sym-lock-font-size)
(put 'sym-lock-font-size 'permanent-local t)

(defvar sym-lock-keywords nil
  "Similar to `font-lock-keywords'.")
(make-variable-buffer-local 'sym-lock-keywords)(put 'sym-lock-keywords 'permanent-local t)

(defvar sym-lock-enabled nil
  "Sym-Lock switch.")
(make-variable-buffer-local 'sym-lock-enabled)
(put 'sym-lock-enabled 'permanent-local t)

(defvar sym-lock-color (face-foreground 'default)
  "*Sym-Lock default color in `font-lock-use-colors' mode.")
(make-variable-buffer-local 'sym-lock-color)
(put 'sym-lock-color 'permanent-local t)

(defvar sym-lock-mouse-face 'default
  "*Face for symbols when under mouse.")
(make-variable-buffer-local 'sym-lock-mouse-face)
(put 'sym-lock-mouse-face 'permanent-local t)

(defvar sym-lock-mouse-face-enabled t
  "Mouse face switch.")
(make-variable-buffer-local 'sym-lock-mouse-face-enabled)
(put 'sym-lock-mouse-face-enabled 'permanent-local t)

(defun sym-lock-gen-symbol (&optional prefix)
  "Generate a new internal symbol."
  ;; where is the standard function to do this ?
  (setq sym-lock-sym-count (+ sym-lock-sym-count 1))
  (intern (concat "sym-lock-gen-" (or prefix "") 
		  (int-to-string sym-lock-sym-count))))

(defun sym-lock-make-symbols-atomic (&optional begin end)
  "Function to make symbol faces atomic."
  (if sym-lock-enabled
      (map-extents 
       (lambda (extent maparg)
	 (let ((face (extent-face extent)) (ext))
	   (if (and face (setq ext (face-property face 'sym-lock-remap)))
	       (progn
		 (if (numberp ext)
		     (set-extent-endpoints
		      extent (- (extent-start-position extent) ext)
		      (extent-end-position extent)))
		 (if ext
		     (progn
		       (if sym-lock-mouse-face-enabled
			   (set-extent-property extent 'mouse-face
						sym-lock-mouse-face))
		       (set-extent-property extent 'atomic t)
		       (set-extent-property extent 'start-open t))))))
	 nil)
       (current-buffer)
       (if begin (save-excursion (goto-char begin) (beginning-of-line) (point))
	 (point-min))
       (if end (save-excursion (goto-char end) (end-of-line) (point))
	 (point-max))
       nil nil)))

(defun sym-lock-compute-font-size ()
  "Computes the size of the \"better\" symbol font."
  (let ((num (if (fboundp 'face-height)
		 (face-height 'default)
	       (let ((str (face-font 'default)))
		 (string-match "-[^-]*-[^-]*-[^-]*-[^-]*-[^-]*-[^-]*-\\([^-]*\\)-.*" str)
		 (string-to-number (substring str (match-beginning 1)
					      (match-end 1))))))
	(maxsize 100) (size) (oldsize)
	(lf (list-fonts "-adobe-symbol-medium-r-normal--*")))
    (while (and lf maxsize)
      (string-match "-[^-]*-[^-]*-[^-]*-[^-]*-[^-]*-[^-]*-\\([^-]*\\)-.*"
		    (car lf))
      (setq size (string-to-number (substring (car lf) (match-beginning 1)
					      (match-end 1))))
      (if (and (> size num) (< size maxsize))
	  (setq maxsize nil)
	(setq oldsize size))
      (setq lf (cdr lf)))
    (number-to-string (if (and oldsize (< oldsize 100)) oldsize num))))

(defvar sym-lock-font-name
  (concat "-adobe-symbol-medium-r-normal--"
	  (if sym-lock-font-size sym-lock-font-size
	    (sym-lock-compute-font-size))
	  "-*-*-*-p-*-adobe-fontspecific")
  "Name of the font used by Sym-Lock.")
(make-variable-buffer-local 'sym-lock-font-name)
(put 'sym-lock-font-name 'permanent-local t)

(make-face 'sym-lock-adobe-symbol-face)
(set-face-font 'sym-lock-adobe-symbol-face sym-lock-font-name)

(defun sym-lock-set-foreground ()
  "Set foreground color of Sym-Lock faces."
  (if (and (boundp 'sym-lock-defaults) sym-lock-defaults)
      (let ((l (car sym-lock-defaults))
	    (color (if (and (boundp 'font-lock-use-fonts) font-lock-use-fonts)
		       (face-foreground 'default) sym-lock-color)))
	(if (and (consp l) (eq (car l) 'quote)) (setq l (eval l)))
	(if (symbolp l) (setq l (eval l)))
	(dolist (c l)
	  (setq c (nth 2 c))
	  (if (consp c) (setq c (eval c)))
	  (if (string-match "-adobe-symbol-" (font-name (face-font c)))
	      (set-face-foreground c color))))))

(defun sym-lock-remap-face (pat pos obj atomic)
  "Make a temporary face which remaps the POS char of PAT to the
given OBJ under `sym-lock-adobe-symbol-face' and all other characters to
the empty string. OBJ may either be a string or a character."
  (let* ((name (sym-lock-gen-symbol "face"))
	 (table (make-display-table))
	 (tface (make-face name "sym-lock-remap-face" t)))
    (fillarray table "")
    (aset table (string-to-char (substring pat (1- pos) pos))
	  (if (stringp obj) obj (make-string 1 obj)))
    (set-face-foreground tface (if (and (boundp 'font-lock-use-fonts)
					font-lock-use-fonts)
				   (face-foreground 'default) sym-lock-color))
    (set-face-property tface 'display-table table)
    (set-face-property tface 'font (face-font 'sym-lock-adobe-symbol-face))
    (set-face-property tface 'sym-lock-remap atomic) ; mark it
    tface  ; return face value and not face name
	   ; the temporary face would be otherwise GCed
    ))

(defvar sym-lock-clear-face
  (let* ((name (sym-lock-gen-symbol "face"))
	 (table (make-display-table))
	 (tface (make-face name "sym-lock-remap-face" t)))
    (fillarray table "")
    (set-face-property tface 'display-table table)
    (set-face-property tface 'sym-lock-remap 1) ; mark it
    tface 
    ;; return face value and not face name
    ;; the temporary face would be otherwise GCed
    ))

(defun sym-lock (fl)
  "Create font-lock table entries from a list of (PAT NUM POS OBJ) where
PAT (at NUM) is substituted by OBJ under `sym-lock-adobe-symbol-face'. The
face's extent will become atomic."
  (message "Computing Sym-Lock faces...")
  (setq sym-lock-keywords (sym-lock-rec fl))
  (setq sym-lock-enabled t)
  (message "Computing Sym-Lock faces... done."))

(defun sym-lock-rec (fl)
  (let ((f (car fl)))
    (if f 	      
	(cons (apply 'sym-lock-atom-face f)
	      (sym-lock-rec (cdr fl))))))

(defun sym-lock-atom-face (pat num pos obj &optional override)
  "Define an entry for the font-lock table which substitutes PAT (at NUM) by
OBJ under `sym-lock-adobe-symbol-face'. The face extent will become atomic."
  (list pat num (sym-lock-remap-face pat pos obj t) override))

(defun sym-lock-pre-idle-hook-first ()
  (condition-case nil
      (if (and sym-lock-enabled font-lock-old-extent)
	  (setq sym-lock-ext-start (extent-start-position font-lock-old-extent)
		sym-lock-ext-end (extent-end-position font-lock-old-extent))
	(setq sym-lock-ext-start nil))
    (error (warn "Error caught in `sym-lock-pre-idle-hook-first'"))))

(defun sym-lock-pre-idle-hook-last ()
  (condition-case nil
      (if (and sym-lock-enabled sym-lock-ext-start)
	  (sym-lock-make-symbols-atomic sym-lock-ext-start sym-lock-ext-end))
    (error (warn "Error caught in `sym-lock-pre-idle-hook-last'"))))

(add-hook 'font-lock-after-fontify-buffer-hook
	  'sym-lock-make-symbols-atomic)

(defun sym-lock-enable ()
  "Enable Sym-Lock on this buffer."
  (interactive)
  (if (not sym-lock-keywords)
      (error "No Sym-Lock keywords defined!")
    (setq sym-lock-enabled t)
    (if font-lock-mode
	(progn
	  (setq font-lock-keywords nil) ; Font-Lock explicit-defaults bug!
	  (font-lock-set-defaults t)
	  (font-lock-fontify-buffer)))
    (message "Sym-Lock enabled.")))

(defun sym-lock-disable ()
  "Disable Sym-Lock on this buffer."
  (interactive)
  (if (not sym-lock-keywords)
      (error "No Sym-Lock keywords defined!")
    (setq sym-lock-enabled nil)
    (if font-lock-mode
	(progn
	  (setq font-lock-keywords nil) ; Font-Lock explicit-defaults bug!
	  (font-lock-set-defaults t)
	  (font-lock-fontify-buffer)))
    (message "Sym-Lock disabled.")))

(defun sym-lock-mouse-face-enable ()
  "Enable special face for symbols under mouse."
  (interactive)
  (setq sym-lock-mouse-face-enabled t)
  (if sym-lock-enabled
      (font-lock-fontify-buffer)))

(defun sym-lock-mouse-face-disable ()
  "Disable special face for symbols under mouse."
  (interactive)
  (setq sym-lock-mouse-face-enabled nil)
  (if sym-lock-enabled
      (font-lock-fontify-buffer)))

(defun sym-lock-font-lock-hook ()
  "Function called by `font-lock-mode' for initialization purposes."
  (add-hook 'pre-idle-hook 'sym-lock-pre-idle-hook-first)
  (add-hook 'pre-idle-hook 'sym-lock-pre-idle-hook-last t)
  (if (and (featurep 'sym-lock) sym-lock-enabled
	   font-lock-defaults (boundp 'sym-lock-keywords))
      (progn
	(sym-lock-patch-keywords)
	(sym-lock-set-foreground))))

(defun font-lock-set-defaults (&optional explicit-defaults)
  (when
      (and
       (featurep 'font-lock)
       (if font-lock-auto-fontify
           (not (memq major-mode font-lock-mode-disable-list))
         (memq major-mode font-lock-mode-enable-list))
       (font-lock-set-defaults-1 explicit-defaults)
       (sym-lock-patch-keywords))
    (turn-on-font-lock)))

(defun sym-lock-patch-keywords ()
  (if (and font-lock-keywords sym-lock-enabled
	   (boundp 'sym-lock-keywords)
	   (listp (car font-lock-keywords))
	   (listp (cdar font-lock-keywords))
	   (listp (cddar font-lock-keywords))
	   (or (listp (caddar font-lock-keywords))
	       (not (string-match
		     "sym-lock"
		     (symbol-name
		      (face-name (cadr (cdar
					font-lock-keywords))))))))
      (setq font-lock-keywords (append sym-lock-keywords
				       font-lock-keywords))) t)

(add-menu-button '("Options" "Syntax Highlighting")
		 ["Sym-Lock"
		  (if sym-lock-enabled (sym-lock-disable) (sym-lock-enable))
		  :style toggle :selected sym-lock-enabled
		  :active sym-lock-keywords] "Automatic")

(add-hook 'font-lock-mode-hook 'sym-lock-font-lock-hook)

(provide 'sym-lock)