From ef39cced4a34a9ab666477befe04a88042ee99b5 Mon Sep 17 00:00:00 2001
From: Simon Michael <simon@joyful.com>
Date: Sat, 16 May 2009 21:19:38 +0000
Subject: [PATCH] don't fail when matching an empty pattern, as in "not:"

---
 Ledger/AccountName.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Ledger/AccountName.hs b/Ledger/AccountName.hs
index 6453338c0..33a3a6627 100644
--- a/Ledger/AccountName.hs
+++ b/Ledger/AccountName.hs
@@ -145,4 +145,4 @@ isnegativepat pat = negateprefix `isPrefixOf` pat
 abspat pat = if isnegativepat pat then drop (length negateprefix) pat else pat
 positivepats = filter (not . isnegativepat)
 negativepats = filter isnegativepat
-matchregex pat str = containsRegex (mkRegexWithOpts pat True False) str
+matchregex pat str = null pat || containsRegex (mkRegexWithOpts pat True False) str