[Haskell-cafe] Advice needed on best way to simulate an STL vector

[Brian Hulley]

Cale Gibbard wrote:
> I should perhaps point out that in the development GHC (iirc), there
> is a library called Data.Sequence which uses 2-3 finger trees to get
> rather nice efficient sequences. Operations on both ends (appending or
> dropping) are constant time, while operations in the middle tend to be
> on the order of the logarithm of the distance to the closer of the two
> ends. For instance, concatenation and splitting at a point both have
> complexity proportional to the logarithm of the smaller of the two
> parts involved.

Does anyone know where I can download this from (since I was just about to 
try to implement exactly this myself based on the paper)? I can't find it 
listed in the hierarchical libraries for ghc.

Thanks, Brian.