emacs: Use 'and' instead of 'when' when the return value matters

[notmuch] / emacs / notmuch-wash.el

diff --git a/emacs/notmuch-wash.el b/emacs/notmuch-wash.el
index c3b24cb97eb4f9e74eefca10047f4342de024b27..31fda61f96428d136233367d883a6a71a0cf4580 100644 (file)
--- a/emacs/notmuch-wash.el
+++ b/emacs/notmuch-wash.el
@@ -370,10 +370,10 @@ filename, before trimming any trailing . and - characters."
 
 Return the patch sequence number N from the last \"[PATCH N/M]\"
 style prefix in SUBJECT, or nil if such a prefix can't be found."
-  (when (string-match
-        "^ *\\(\\[[^]]*\\] *\\)*\\[[^]]*?\\([0-9]+\\)/[0-9]+[^]]*\\].*"
-        subject)
-      (string-to-number (substring subject (match-beginning 2) (match-end 2)))))
+  (and (string-match
+       "^ *\\(\\[[^]]*\\] *\\)*\\[[^]]*?\\([0-9]+\\)/[0-9]+[^]]*\\].*"
+       subject)
+       (string-to-number (substring subject (match-beginning 2) (match-end 2)))))
 
 (defun notmuch-wash-subject-to-patch-filename (subject)
   "Convert a patch mail SUBJECT into a filename.