From 9b47b4aa128a5cbee74aa99e5494a0b76890ec4a Mon Sep 17 00:00:00 2001
From: markus <unknown>
Date: Tue, 11 Nov 2003 11:59:21 +0000
Subject: Added a collapse function to Trie

---
 src/GF/Data/RedBlack.hs | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'src/GF/Data/RedBlack.hs')

diff --git a/src/GF/Data/RedBlack.hs b/src/GF/Data/RedBlack.hs
index 8a24c07a3..4ee1f92a6 100644
--- a/src/GF/Data/RedBlack.hs
+++ b/src/GF/Data/RedBlack.hs
@@ -10,6 +10,7 @@
 
 module RedBlack (
                 emptyTree,
+		isEmpty,		
 		Tree,
 		lookupTree,
 		insertTree,
@@ -32,6 +33,10 @@ balance color a x b = T color a x b
 emptyTree :: Tree key el
 emptyTree = E
 
+isEmpty :: Tree key el -> Bool
+isEmpty (E) = True
+isEmpty _   = False
+
 lookupTree :: Ord a => a -> Tree a b -> Maybe b
 lookupTree _ E = Nothing
 lookupTree x (T _ a (y,z) b)
-- 
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