[Haskell-cafe] stream/bytestring questions

Don Stewart dons at galois.com
Sun Feb 17 20:27:25 EST 2008


chad.scherrer:
> > they currently use two different fusion systems. bytestring uses an
> > older version of what is now stream fusion. at some point we'll switch
> > bytestrings over to using the new stuff in the stream-fusion package,
> > since its a lot better.
> 
> Oh, that's pretty interesting. I had assumed bytestring had the latest
> fusion stuff.
> 
> > ah, you assume stream-fusion lists are slower. for list stuff, since
> > 6.8, i've only seen things the same speed or better. but if you have a
> > program doing the wrong thing, it would be worth looking at.
> 
> I was just going by the "Lists to Streams to Nothing At All"  paper.
> That's great that it's gotten faster! Does that mean the path for
> replacing Data.List with this is any clearer?

Not yet. We still don't have a good system for fusing nested concatMaps, 
that GHC likes, which come up when you desugar list comprehensions.

If you can live without too many comprehensions, then the stream-fusion
package is entirely viable.

-- Don


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