Emmanuel CHANTREAU wrote:
In my futur program, it use a lot of binary trees with strings (words) as leaf. There is just arround 1000 words and they will appear a lot of times. The program will possibly consume a lot of process and memory (it is a mathematics proover).
If your strings are indeed leaves, then chances are that you share them a lot and there's nothing much to worry about. For instance, the following complete binary tree data Tree a = Leaf a | Branch (Tree a) (Tree a) example a = tree 100 where tree 0 = Leaf a tree n = let t = tree (n-1) in Branch t t uses only linear space and the argument a is stored exactly once. I'm not sure whether this answers your question, though, also because it depends on what exactly you want. I suggest writing a tiny prototype of your idea and asking on the mailing list again when there are any performance problems. Also, knowing Haskell's evaluation model helps a lot http://en.wikibooks.org/wiki/Haskell/Graph_reduction Regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com