Re: [Haskell-cafe] Pure hashtable library

Jules Bean wrote:

Jason Dusek wrote:

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Jules Bean wrote:

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Jason Dusek wrote:

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I would much rather have a pure Trie that is foldable. If we have a Trie, we get a space efficient sorted list, too.

Well, Data.Sequence can be used as a space efficient sorted list which is Foldable - if you make the decision to insert elements into it in a sorted way, obviously.

What advantages would a Trie have over Data.Sequence?

A trie is guaranteed sorted -- so using a trie amounts to a "type level" guarantee for binary search and any other algorithm that relies on sortedness.

...No more so than a simple wrapper over a Data.Sequence which puts the elements in the right place.

If by a wrapper you mean a function, well that's not type level at all. A binary search that insists on tries will, with a correct trie implementation, behave correctly on every input; a binary search that works with `Data.Sequence` will fail on a substantial portion of the inputs accepted by the type system, regardless of the data structure's correctness. -- _jsn