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[Emacs-diffs] Changes to emacs/lisp/emacs-lisp/assoc.el [lexbind]
From: |
Miles Bader |
Subject: |
[Emacs-diffs] Changes to emacs/lisp/emacs-lisp/assoc.el [lexbind] |
Date: |
Tue, 14 Oct 2003 19:32:21 -0400 |
Index: emacs/lisp/emacs-lisp/assoc.el
diff -c /dev/null emacs/lisp/emacs-lisp/assoc.el:1.4.18.1
*** /dev/null Tue Oct 14 19:32:21 2003
--- emacs/lisp/emacs-lisp/assoc.el Tue Oct 14 19:32:20 2003
***************
*** 0 ****
--- 1,141 ----
+ ;;; assoc.el --- insert/delete/sort functions on association lists
+
+ ;; Copyright (C) 1996 Free Software Foundation, Inc.
+
+ ;; Author: Barry A. Warsaw <address@hidden>
+ ;; Keywords: extensions
+
+ ;; This file is part of GNU Emacs.
+
+ ;; GNU Emacs 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.
+
+ ;; GNU Emacs 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:
+
+ ;; Association list utilities providing insertion, deletion, sorting
+ ;; fetching off key-value pairs in association lists.
+
+ ;;; Code:
+
+ (defun asort (alist-symbol key)
+ "Move a specified key-value pair to the head of an alist.
+ The alist is referenced by ALIST-SYMBOL. Key-value pair to move to
+ head is one matching KEY. Returns the sorted list and doesn't affect
+ the order of any other key-value pair. Side effect sets alist to new
+ sorted list."
+ (set alist-symbol
+ (sort (copy-alist (eval alist-symbol))
+ (function (lambda (a b) (equal (car a) key))))))
+
+
+ (defun aelement (key value)
+ "Makes a list of a cons cell containing car of KEY and cdr of VALUE.
+ The returned list is suitable as an element of an alist."
+ (list (cons key value)))
+
+
+ (defun aheadsym (alist)
+ "Return the key symbol at the head of ALIST."
+ (car (car alist)))
+
+
+ (defun anot-head-p (alist key)
+ "Find out if a specified key-value pair is not at the head of an alist.
+ The alist to check is specified by ALIST and the key-value pair is the
+ one matching the supplied KEY. Returns nil if ALIST is nil, or if
+ key-value pair is at the head of the alist. Returns t if key-value
+ pair is not at the head of alist. ALIST is not altered."
+ (not (equal (aheadsym alist) key)))
+
+
+ (defun aput (alist-symbol key &optional value)
+ "Inserts a key-value pair into an alist.
+ The alist is referenced by ALIST-SYMBOL. The key-value pair is made
+ from KEY and optionally, VALUE. Returns the altered alist or nil if
+ ALIST is nil.
+
+ If the key-value pair referenced by KEY can be found in the alist, and
+ VALUE is supplied non-nil, then the value of KEY will be set to VALUE.
+ If VALUE is not supplied, or is nil, the key-value pair will not be
+ modified, but will be moved to the head of the alist. If the key-value
+ pair cannot be found in the alist, it will be inserted into the head
+ of the alist (with value nil if VALUE is nil or not supplied)."
+ (let ((elem (aelement key value))
+ alist)
+ (asort alist-symbol key)
+ (setq alist (eval alist-symbol))
+ (cond ((null alist) (set alist-symbol elem))
+ ((anot-head-p alist key) (set alist-symbol (nconc elem alist)))
+ (value (setcar alist (car elem)))
+ (t alist))))
+
+
+ (defun adelete (alist-symbol key)
+ "Delete a key-value pair from the alist.
+ Alist is referenced by ALIST-SYMBOL and the key-value pair to remove
+ is pair matching KEY. Returns the altered alist."
+ (asort alist-symbol key)
+ (let ((alist (eval alist-symbol)))
+ (cond ((null alist) nil)
+ ((anot-head-p alist key) alist)
+ (t (set alist-symbol (cdr alist))))))
+
+
+ (defun aget (alist key &optional keynil-p)
+ "Returns the value in ALIST that is associated with KEY.
+ Optional KEYNIL-P describes what to do if the value associated with
+ KEY is nil. If KEYNIL-P is not supplied or is nil, and the value is
+ nil, then KEY is returned. If KEYNIL-P is non-nil, then nil would be
+ returned.
+
+ If no key-value pair matching KEY could be found in ALIST, or ALIST is
+ nil then nil is returned. ALIST is not altered."
+ (let ((copy (copy-alist alist)))
+ (cond ((null alist) nil)
+ ((progn (asort 'copy key)
+ (anot-head-p copy key)) nil)
+ ((cdr (car copy)))
+ (keynil-p nil)
+ ((car (car copy)))
+ (t nil))))
+
+
+ (defun amake (alist-symbol keylist &optional valuelist)
+ "Make an association list.
+ The association list is attached to the alist referenced by
+ ALIST-SYMBOL. Each element in the KEYLIST becomes a key and is
+ associated with the value in VALUELIST with the same index. If
+ VALUELIST is not supplied or is nil, then each key in KEYLIST is
+ associated with nil.
+
+ KEYLIST and VALUELIST should have the same number of elements, but
+ this isn't enforced. If VALUELIST is smaller than KEYLIST, remaining
+ keys are associated with nil. If VALUELIST is larger than KEYLIST,
+ extra values are ignored. Returns the created alist."
+ (let ((keycar (car keylist))
+ (keycdr (cdr keylist))
+ (valcar (car valuelist))
+ (valcdr (cdr valuelist)))
+ (cond ((null keycdr)
+ (aput alist-symbol keycar valcar))
+ (t
+ (amake alist-symbol keycdr valcdr)
+ (aput alist-symbol keycar valcar))))
+ (eval alist-symbol))
+
+ (provide 'assoc)
+
+ ;;; arch-tag: 3e58bd89-d912-4b74-a0dc-6ed9735922bc
+ ;;; assoc.el ends here
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