From 61456fd9ca6189a689ac0911f0e7260ce86e76d0 Mon Sep 17 00:00:00 2001
From: bringert <bringert@cs.chalmers.se>
Date: Sat, 24 Mar 2007 17:26:21 +0000
Subject: [PATCH] Better debugging output when SRG generation crashes because
 of a missing category.

---
 src/GF/Speech/SRG.hs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/GF/Speech/SRG.hs b/src/GF/Speech/SRG.hs
index 995eb3b2e..8c3c5e02c 100644
--- a/src/GF/Speech/SRG.hs
+++ b/src/GF/Speech/SRG.hs
@@ -185,7 +185,9 @@ ungroupTokens = joinRE . mapRE (symbol (RESymbol . Cat) (REConcat . map (RESymbo
 --
 
 lookupFM_ :: (Ord key, Show key) => Map key elt -> key -> elt
-lookupFM_ fm k = Map.findWithDefault (error $ "Key not found: " ++ show k) k fm
+lookupFM_ fm k = Map.findWithDefault err k fm
+  where err = error $ "Key not found: " ++ show k
+                      ++ "\namong " ++ show (Map.keys fm)
 
 prtS :: Print a => a -> ShowS
 prtS = showString . prt
\ No newline at end of file