;;; pure-pr-filter.el --- Filter function management for PURE

;; Copyright (C) 2000 Project Pure.

;; Author: SHIMADA Mitsunobu <simm@pure.fan.gr.jp>
;; Keywords: PURE, process, filter

;; $Id: pure-pr-filter.el,v 1.3 2001/06/06 14:24:51 simm Exp $

;; 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 2, or (at your option)
;; any later version.

;; This file 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 GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; PURE means "Primitive Universal Relay-chat Environment"
;; PR means "process"

;;; Code:

(require 'pure-bl)

(defconst pure-pr-filter-local-variables
  '([pure-pr-filter-parser nil "Parser function fore PURE filter function."])
  "List of buffer-local variables for PURE filter function management.")

(defun pure-pr-filter-set-filter (proc func)
  "Set filter function for PURE.
Filter function is `pure-pr-filter-loop', and set parser function for PURE filter function.
This function is called when first setting of filter."
  (save-excursion
    (set-buffer (process-buffer proc))
    (pure-bl-defvar pure-pr-filter-local-variables)
    (pure-bl-make-current pure-pr-filter-local-variables)
    (setq pure-pr-filter-parser func)
    (set-process-filter proc 'pure-pr-filter-loop)))

(defun pure-pr-filter-set-parser (proc func)
  "Set parser function for PURE filter function.
This function is called when changing filter body."
  (save-excursion
    (set-buffer (process-buffer proc))
    (setq pure-pr-filter-parser func)))

(defun pure-pr-filter-loop (proc msg)
  "Main loop of PURE filter function.
This function is skelton and main process is pointed by `pure-pr-filter-parser'.
So remember to set parser function by `pure-pr-filter-set-filter' or `pure-pr-filter-set-parser'."
  (save-match-data
    (save-excursion
      (set-buffer (process-buffer proc))
      (goto-char (point-max))
      (insert msg)
      (while (and (goto-char (point-min))
		  (= 0 (forward-line 1))
		  (bolp))
	(while (and (char-before) (or (= 10 (char-before)) (= 13 (char-before))))
	  (delete-backward-char 1))
	(save-restriction
	  (narrow-to-region (point-min) (point))
	  (goto-char (point-min))
	  (if (fboundp pure-pr-filter-parser)
	      (funcall pure-pr-filter-parser proc))
	  (delete-region (point-min) (point-max)))))))

;; That's all
(provide 'pure-pr-filter)

;;; pure-pr-filter.el ends here