>From 11fea59d41063b3511a84a0d783cfa2016ed68c4 Mon Sep 17 00:00:00 2001
From: Alex Kost <address@hidden>
Date: Sat, 31 Oct 2015 21:36:41 +0300
Subject: [PATCH 1/2] emacs: Add 'guix-hash-char-regexp'.

* emacs/guix-utils.el (guix-hash-char-regexp): New constant.
* emacs/guix-prettify.el (guix-prettify-regexp): Use it.
---
 emacs/guix-prettify.el | 8 ++++----
 emacs/guix-utils.el    | 6 ++++++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/emacs/guix-prettify.el b/emacs/guix-prettify.el
index 38d72e8..0411aee 100644
--- a/emacs/guix-prettify.el
+++ b/emacs/guix-prettify.el
@@ -84,10 +84,10 @@ disabling `guix-prettify-mode' a little faster."
   ;; http://hydra.gnu.org/nar/…-foo-0.1
   ;; http://hydra.gnu.org/log/…-foo-0.1
 
-  (rx "/" (or "store" "nar" "log") "/"
-      ;; Hash-parts do not include "e", "o", "u" and "t".  See base32Chars
-      ;; at <https://github.com/NixOS/nix/blob/master/src/libutil/hash.cc>
-      (group (= 32 (any "0-9" "a-d" "f-n" "p-s" "v-z"))))
+  (rx-to-string
+   `(and "/" (or "store" "nar" "log") "/"
+         (group (= 32 (regexp ,guix-hash-char-regexp))))
+   t)
   "Regexp matching file names for prettifying.
 
 Disable `guix-prettify-mode' before modifying this variable and
diff --git a/emacs/guix-utils.el b/emacs/guix-utils.el
index d1f088b..d8dad91 100644
--- a/emacs/guix-utils.el
+++ b/emacs/guix-utils.el
@@ -33,6 +33,12 @@
   "String used to format time values.
 For possible formats, see `format-time-string'.")
 
+(defconst guix-hash-char-regexp
+  ;; Hash parts do not include "e", "o", "u" and "t".  See base32Chars
+  ;; at <https://github.com/NixOS/nix/blob/master/src/libutil/hash.cc>.
+  "[0-9a-df-np-sv-z]"
+  "Regexp matching a character used by Nix base32 hash.")
+
 (defun guix-get-string (val &optional face)
   "Convert VAL into a string and return it.
 
-- 
2.5.0