The bytestring-trie package provides an efficient implementation of tries mapping ByteString to values. The implementation is based on Okasaki's big-endian patricia trees, à la IntMap. We first trie on the elements of ByteString and then trie on the big-endian bit representation of those elements. Patricia trees have efficient algorithms for union and other merging operations, but they're also quick for lookups and insertions.

If you are only interested in being able to associate individual ByteStrings to values, then you may prefer the hashmap package which is faster for those only needing a map-like structure. This package is intended for those who need the extra capabilities that a trie-like structure can offer (e.g., structure sharing to reduce memory costs for highly redundant keys, taking the submap of all keys with a given prefix, contextual mapping, extracting the minimum and maximum keys, etc.)

This is a simple package and should be easy to install. You should be able to use one of the following standard methods to install it.

-- With cabal-install and without the source:
$> cabal install bytestring-trie

-- With cabal-install and with the source already:
$> cd bytestring-trie
$> cabal install

-- Without cabal-install, but with the source already:
$> cd bytestring-trie
$> runhaskell Setup.hs configure --user
$> runhaskell Setup.hs build
$> runhaskell Setup.hs haddock --hyperlink-source
$> runhaskell Setup.hs copy
$> runhaskell Setup.hs register

The Haddock step is optional.

The implementation is quite portable, relying only on a few basic language extensions. The complete list of extensions used is:

• CPP
• MagicHash
• NoImplicitPrelude

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