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/Trie.hs | 9 +++++++++
 1 file changed, 9 insertions(+)

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

diff --git a/src/GF/Data/Trie.hs b/src/GF/Data/Trie.hs
index 0a0a4472b..724df0761 100644
--- a/src/GF/Data/Trie.hs
+++ b/src/GF/Data/Trie.hs
@@ -10,6 +10,7 @@
 
 module Trie (
              tcompile,
+	     collapse,
              Trie,
 	     trieLookup,
 	     decompose,
@@ -35,6 +36,14 @@ optimize :: TrieT -> Trie
 optimize (TrieT (xs,res)) = Trie ([(c,optimize t) | (c,t) <- xs] |->+ empty,
 				  res)
 
+collapse :: Trie -> [(String,[(Attr,String)])]
+collapse trie = collapse' trie []
+  where collapse' (Trie (map,(x:xs))) s = if (isEmpty map) then [(reverse s,(x:xs))]
+	                                   else (reverse s,(x:xs)):
+					    concat [ collapse' trie (c:s) | (c,trie) <- flatten map]
+	collapse' (Trie (map,[])) s
+	 = concat [ collapse' trie (c:s) | (c,trie) <- flatten map]
+
 tcompile :: [(String,[(Attr,String)])] -> Trie
 tcompile xs = optimize $ build xs emptyTrie
 
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