Owning SYB

Claus Reinke claus.reinke at talk21.com
Mon Jul 28 14:01:37 EDT 2008

>[I'm spamming libraries at haskell.org too, in case anyone interested in generics 
>is not on generics at haskell.org.]

Given the low number of responders on generics@, it may well be easier
to continue on libraries@, cc-ing anyone on generics@ who isn't on libraries at .

>As you know, Claus has offered a somewhat-detailed proposal for changes to the 
>SYB library (below).  But I don't think that we have an active maintainer for any 
>of the generic-programming libraries (esp SYB) apart from Uniplate.  Then there's 
>the related question of what generic-programming technology to promote for clients 
>of the GHC API.

Thanks for raising this, Simon. I've actually been holding an email summarizing 
several issues (not just performance of default traversal schemes) that I'd like 
to see adressed in Syb (holding because the Syb authors were/are away, and 
because my performance improvement experiments are currently stuck on a
GHC optimization issue). I'll send that email separately now.

>The obvious candidates are Claus himself, or Alexey Rodriguez, or Thomas 
>Schilling; but perhaps there are others too?  Maybe no one has stepped forward 
>because you all think that I'm on the job!  But I'm not... I'm busy with GHC itself, 
>and would love a maintainer for SYB and associated gubbins.  I fear that 
>otherwise we may lose the benefits of Claus's homework.

I'm quite willing to continue pursueing the issues I've raised until I can
make concrete suggestions for improving Syb, including summing up the
code changes I've been adding to my various messages (certainly there
should be patches to accompany proposal tickets in the library process, 
and I should collect all the strands of text into a single document). 

I have been waiting for the original Syb authors to return from their 
well-earned summer camps, but there should probably be a Wiki
page somewhere specifically for discussing Syb-related issues and solutions
(meanwhile, I've started collecting links/info related to GHC Api type 
traversals here, including the main Syb issues:
http://hackage.haskell.org/trac/ghc/wiki/GhcApiAstTraversals , please
feel free to copy stuff from there to a Syb-specific page).

But I wouldn't want to take on ownership of Syb at this point, for two 
reasons, both motivational: (a) it helps to have someone else to "blame" 
when the consequences of gfoldl's type once again hurt my brain;-),
(b) it is really frustrating to get so little interest in these issues, well, we 
haven't even managed to start a proper discussion on any of the lists
I've tried, and as long as there is a Syb owner other than myself, at 
least I won't be talking entirely to myself!-)


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