Re: [Haskell-cafe] ANN: unordered-containers - a new, faster hashing-based containers library

On Sat, Feb 19, 2011 at 7:27 PM, Sterling Clover wrote:

On Sat, Feb 19, 2011 at 3:04 PM, Johan Tibell wrote:

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On Sat, Feb 19, 2011 at 11:58 AM, Louis Wasserman wrote:

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A couple thoughts: size takes O(n). That's just depressing. Really.

This applies to all the container types. We could support O(1) size at the cost of slowing down e.g lookup, insert, and delete a little bit. I haven't measure how much yet. Would it be worth it?

Getting a bit picky, but for the record, Data.Map and Data.Sequence provide O(1) size, and Data.HashTable I believe stores the information but doesn't expose it from its tiny API. That's not an argument either way for what a HashMap should do, however :-)

NB: Data.IntMap, which Data.HashMap is based on, actually only provides O(n) size. -Edward