Function: asort

asort is a byte-compiled function defined in assoc.el.gz.

Signature

(asort ALIST-SYMBOL KEY)

Documentation

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.

Source Code

;; Defined in /usr/src/emacs/lisp/obsolete/assoc.el.gz
;;; assoc.el --- insert/delete functions on association lists  -*- lexical-binding: t -*-

;; Copyright (C) 1996, 2001-2022 Free Software Foundation, Inc.

;; Author: Barry A. Warsaw <bwarsaw@cen.com>
;; Keywords: extensions
;; Obsolete-since: 24.3

;; 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 3 of the License, 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.  If not, see <https://www.gnu.org/licenses/>.

;;; 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 (symbol-value alist-symbol))
             (lambda (a _b) (equal (car a) key)))))