wren:
Alex Mason wrote:
TernaryTrees is a package that extends Data.Set ad Data.Map with some ternary tree structures, based on the article [http://www.pcplus.co.uk/node/3074/] .
For the string (or rather ByteString) version:
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/bytestring-trie
Which has a number of other significant performance improvements (e.g. node fusion, ByteString instead of String) and a highly expressive interface. Because it uses ByteStrings it can trie any type which can be serialized into a vector of bits[1], albeit indirectly.
The real trick with tries is not in just having them[2], it's in having the right interface to make use of what they're good at. For example, if I have multiple tries, I'd like to merge them without doing it element by element[3]. Or if I know I'm going to be making a number of similar queries, it'd be nice if I could cache my position in the trie[4] to avoid repeating the work for the prefixes of all my queries[5]. Using tricks like these leads to significant improvements over using them like hashtables; tries aren't hashtables just like lists aren't arrays.
Do you have benchmarks?