On 5/23/05, Tomasz Zielonka
On Mon, May 23, 2005 at 12:13:48PM +0100, Ross Paterson wrote:
A general implementation of sequences (based on work with Ralf Hinze) can be found at
http://www.soi.city.ac.uk/~ross/software/html/Data.Sequence.html http://www.soi.city.ac.uk/~ross/software/Data/Sequence.hs
Our experiments indicate that its performance is comparable to (and sometimes better than) the best known persistent implementations(*). Non-persistent implementations are typically faster, but you need to be more careful when using them.
I'd like to propose this for base.
Comments welcome.
Another thing: O(1) reverse would be very nice if it could be implemented with no overhead for other operations ;-)
That should be trivial to implement. Just add a bit in the Seq data type which indicates whether the sequence should be treated backwards or forwards. The reverse operation then just toggles that bit. Or am I missing something? Also, I have some comments about the complexities in the documentation. First of all I think it is useful to say what exactly indices like n and i refer to even if it might not be that hard to figure out. Secondly it seems that the complexity of the indexing functions is wrong. Shouldn't they be O(log(min(i,n-i)))? Otherwise I think it looks like a really useful library! /Josef