David Menendez wrote:
Alec Berryman wrote:
I don't know of a library to intern strings, but it's not too hard to implement. I couldn't find the code I wrote to do this, but I looked around a bit and this is about what I remember doing:
http://www.haskell.org/pipermail/haskell-cafe/2005-June/010335.html
For the application I was using, interning strings did provide a significant reduction in memory, but for whatever reason didn't help with speed.
I'd use a trie. Edison provides Data.Edison.Assoc.TernaryTrie, and there are a few other trie packages at hackage.
One of those: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/bytestring-trie also uses ByteStrings instead of Strings. This will further reduce your memory footprint and will improve performance (because of cache consistency, less pointer chasing, and using C's fast string comparison function). I've been meaning to write a ByteString interning library on top of it, but haven't found the time just yet. -- Live well, ~wren