emacs: Add and use 'guix-while-search'.

* emacs/guix-utils.el (guix-while-search): New macro.
* emacs/guix-pcomplete.el (guix-pcomplete-run-guix-and-search): Use it.
* emacs/guix-prettify.el (guix-prettify-decompose-buffer): Likewise.

emacs/guix-pcomplete.el

@@ -105,9 +105,8 @@ Return a list of strings matching REGEXP.
 GROUP specifies a parenthesized expression used in REGEXP."
   (with-temp-buffer
     (apply #'guix-pcomplete-run-guix args)
-    (goto-char (point-min))
     (let (result)
-      (while (re-search-forward regexp nil t)
+      (guix-while-search regexp
         (push (match-string-no-properties group) result))
       (nreverse result))))
 

emacs/guix-prettify.el

@@ -1,6 +1,6 @@
 ;;; guix-prettify.el --- Prettify Guix store file names
 
-;; Copyright © 2014 Alex Kost <alezost@gmail.com>
+;; Copyright © 2014, 2015 Alex Kost <alezost@gmail.com>
 
 ;; This file is part of GNU Guix.
 
@@ -47,6 +47,8 @@
 
 ;;; Code:
 
+(require 'guix-utils)
+
 (defgroup guix-prettify nil
   "Prettify Guix store file names."
   :prefix "guix-prettify-"
@@ -137,13 +139,11 @@ enabling/disabling `guix-prettify-mode'.  If nil, do nothing.")
           (remove-text-properties (point-min)
                                   (point-max)
                                   '(composition nil))
-        (save-excursion
-          (goto-char (point-min))
-          (while (re-search-forward guix-prettify-regexp nil t)
+        (guix-while-search guix-prettify-regexp
           (remove-text-properties
            (match-beginning guix-prettify-regexp-group)
            (match-end       guix-prettify-regexp-group)
-             '(composition nil))))))))
+           '(composition nil)))))))
 
 ;;;###autoload
 (define-minor-mode guix-prettify-mode

emacs/guix-utils.el

@@ -160,6 +160,14 @@ accessed with KEYS."
       (find-file file)
     (message "File '%s' does not exist." file)))
 
+(defmacro guix-while-search (regexp &rest body)
+  "Evaluate BODY after each search for REGEXP in the current buffer."
+  (declare (indent 1) (debug t))
+  `(save-excursion
+     (goto-char (point-min))
+     (while (re-search-forward ,regexp nil t)
+       ,@body)))
+
 
 ;;; Diff