--- /dev/null
+;;; alist.el --- utility functions about assoc-list
+
+;; Copyright (C) 1993,1994,1995,1996 Free Software Foundation, Inc.
+
+;; Author: MORIOKA Tomohiko <morioka@jaist.ac.jp>
+;; Version:
+;; $Id: alist.el,v 0.0 1997-02-28 02:18:23 tmorioka Exp $
+;; Keywords: alist
+
+;; This file is part of SEMI (SEMI is Emacs MIME Interfaces).
+
+;; 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, 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 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.
+
+;;; Code:
+
+(defun put-alist (item value alist)
+ "Modify ALIST to set VALUE to ITEM.
+If there is a pair whose car is ITEM, replace its cdr by VALUE.
+If there is not such pair, create new pair (ITEM . VALUE) and
+return new alist whose car is the new pair and cdr is ALIST.
+\[tomo's ELIS like function]"
+ (let ((pair (assoc item alist)))
+ (if pair
+ (progn
+ (setcdr pair value)
+ alist)
+ (cons (cons item value) alist)
+ )))
+
+(defun del-alist (item alist)
+ "If there is a pair whose key is ITEM, delete it from ALIST.
+\[tomo's ELIS emulating function]"
+ (if (equal item (car (car alist)))
+ (cdr alist)
+ (let ((pr alist)
+ (r (cdr alist))
+ )
+ (catch 'tag
+ (while (not (null r))
+ (if (equal item (car (car r)))
+ (progn
+ (rplacd pr (cdr r))
+ (throw 'tag alist)))
+ (setq pr r)
+ (setq r (cdr r))
+ )
+ alist))))
+
+(defun set-alist (symbol item value)
+ "Modify a alist indicated by SYMBOL to set VALUE to ITEM."
+ (or (boundp symbol)
+ (set symbol nil)
+ )
+ (set symbol (put-alist item value (symbol-value symbol)))
+ )
+
+(defun remove-alist (symbol item)
+ "Remove ITEM from the alist indicated by SYMBOL."
+ (and (boundp symbol)
+ (set symbol (del-alist item (symbol-value symbol)))
+ ))
+
+(defun modify-alist (modifier default)
+ "Modify alist DEFAULT into alist MODIFIER."
+ (mapcar (function
+ (lambda (as)
+ (setq default (put-alist (car as)(cdr as) default))
+ ))
+ modifier)
+ default)
+
+(defun set-modified-alist (sym modifier)
+ "Modify a value of a symbol SYM into alist MODIFIER.
+The symbol SYM should be alist. If it is not bound,
+its value regard as nil."
+ (if (not (boundp sym))
+ (set sym nil)
+ )
+ (set sym (modify-alist modifier (eval sym)))
+ )
+
+
+;;; @ end
+;;;
+
+(provide 'alist)
+
+;;; alist.el ends here