mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-11-25 07:28:20 +00:00
142 lines
5.1 KiB
EmacsLisp
142 lines
5.1 KiB
EmacsLisp
;;; assoc.el --- insert/delete/sort functions on association lists
|
|
|
|
;; Copyright (C) 1996, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
|
|
|
|
;; Author: Barry A. Warsaw <bwarsaw@cen.com>
|
|
;; 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., 51 Franklin Street, Fifth Floor,
|
|
;; Boston, MA 02110-1301, 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
|