Hello folks, This is an announcement for an alpha release of the new collections package I (and others, see below) have been working on. It's still far from perfect, but I hope it's already a good choice for many use cases of collection data structures. Also, "release early, release often" : I hope releasing now will allow me to keep a on improving it at a steady rate. Darcs repo: http://darcs.haskell.org/packages/collections/ Documentation: http://users.skynet.be/jyp/html/ (documentation for base package can be found there as well, for the purpose of cross-referencing) It is originally designed to depend on the upcoming version of the base package; however I've arranged it to work with current version as well. (Meaning you can use it as a cabal package with GHC 6.4) Please try out and let me know what you think. 0.9rc1 release notes: * Efficient AVL-tree based implementations of Set and Map (by Adrian Hey) * efficient conversion routines between those Sets and Maps * Class-based Collection framework for abstracting over Collections, Sequences, Maps, Sets. * Nicely corresponds to the current API. In a lot of cases, just removing the module prefix does the trick. * QuickCheck-based validation of the instances. * Benchmark suite * Adaptation of Ross Paterson's Foldable class to MPTC+FD. * Trie data type, to map sequential types (eg. lists) to keys. * Efficient Set type for enumerations. (David F. Place) --- Cheers, JP.