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diff --git a/emacs/guix-entry.el b/emacs/guix-entry.el
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+;;; guix-entry.el --- 'Entry' type  -*- lexical-binding: t -*-
+
+;; Copyright © 2015 Alex Kost <alezost@gmail.com>
+
+;; This file is part of GNU Guix.
+
+;; GNU Guix 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 Guix 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; This file provides an API for 'entry' type which is just an alist of
+;; KEY/VALUE pairs (KEY should be a symbol) with the required 'id' KEY.
+
+;;; Code:
+
+(require 'cl-lib)
+(require 'guix-utils)
+
+(defalias 'guix-entry-value #'guix-assq-value)
+
+(defun guix-entry-id (entry)
+  "Return ENTRY ID."
+  (guix-entry-value entry 'id))
+
+(defun guix-entry-by-id (id entries)
+  "Return an entry from ENTRIES by its ID."
+  (cl-find-if (lambda (entry)
+                (equal (guix-entry-id entry) id))
+              entries))
+
+(defun guix-entries-by-ids (ids entries)
+  "Return entries with IDS (a list of identifiers) from ENTRIES."
+  (cl-remove-if-not (lambda (entry)
+                      (member (guix-entry-id entry) ids))
+                    entries))
+
+(defun guix-replace-entry (id new-entry entries)
+  "Replace an entry with ID from ENTRIES by NEW-ENTRY.
+Return a list of entries with the replaced entry."
+  (cl-substitute-if new-entry
+                    (lambda (entry)
+                      (equal id (guix-entry-id entry)))
+                    entries
+                    :count 1))
+
+(provide 'guix-entry)
+
+;;; guix-entry.el ends here