[Haskell-cafe] SYB3 codebase

Mads Lindstrøm mads_lindstroem at yahoo.dk
Sun Oct 21 03:06:13 EDT 2007

Hi Ian

Ian Lynagh:
> On Fri, Oct 19, 2007 at 07:59:37PM +0200, Mads Lindstrøm wrote:
> > 
> > http://hackage.haskell.org/cgi-bin/hackage-scripts/package/syb-with-class-0.3
> > (hereafter know as HappS-SYB3). HappS-SYB3 is based on the SYB3 code
> > you mention, but the code has been changed quite a bit compared to
> > using the Shelarcy patch. So it will properly require some more work.
> Can you explain what you mean by "require some more work" please?
> As far as I can remember the API provided by the code has not changed,
> the changes have only been improvements to the internal code.

>From the original SYB3:
gfoldl :: ctx ()
       -> (forall a b. Data ctx a => c (a -> b) -> a -> c b)
       -> (forall g. g -> c g)
       -> a -> c a

>From Happs-SYB3:
gfoldl :: Proxy ctx
       -> (forall b c. Data ctx b => w (b -> c) -> b -> w c)
       -> (forall g. g -> w g)
       -> a -> w a

looking at the first argument you will see a slight difference. Also the
original SYB3 contains the function gfoldlAccum, which the HappS version
do not contain. There are other differences too.

> > I have not been able to find any documentation for HappS-SYB3.
> The SYB3 paper describes how to use it, but other than that there is no
> documentation. Of course, if anyone wanted to write some other docs then
> that would be great!
Yes, that would be great. 

> > Thus I have no idea of his position on my usage of HappS-SYB3.
> I'm not sure exactly what you're asking. syb-with-class is
> BSD3-licenced, and anyone is free to use it for whatever they want
> within the terms of that licence.

I was not referring to the license. To be earnest I can see that I was
not clear about what I was referring to :(

I was thinking about the level of support. 

Was this just a library to support HappS, and people could use it but
there would be no help if they ran into problems. Or would it receive
the same support as the HappS project gives to there users.

> Thanks
> Ian



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