From 92f22c8f5c13c381d323caeffe17b6dab4c2d927 Mon Sep 17 00:00:00 2001
From: bringert <bringert@cs.chalmers.se>
Date: Fri, 20 Jan 2006 18:20:02 +0000
Subject: Use right start category names in si command.

---
 src/GF/Data/Utilities.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'src/GF/Data')

diff --git a/src/GF/Data/Utilities.hs b/src/GF/Data/Utilities.hs
index a5ceb08d2..aaadad1fe 100644
--- a/src/GF/Data/Utilities.hs
+++ b/src/GF/Data/Utilities.hs
@@ -81,8 +81,8 @@ unionAll = nub . concat
 
 -- | Like 'lookup', but fails if the argument is not found,
 --   instead of returning Nothing.
-lookup' :: Eq a => a -> [(a,b)] -> b
-lookup' x = fromJust . lookup x
+lookup' :: (Show a, Eq a) => a -> [(a,b)] -> b
+lookup' x = fromMaybe (error $ "Not found: " ++ show x) . lookup x
 
 -- | Like 'find', but fails if nothing is found.
 find' :: (a -> Bool) -> [a] -> a
-- 
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