[Hs-Generics] Re: Owning SYB

Alexey Rodriguez mrchebas at gmail.com
Tue Jul 29 10:10:00 EDT 2008

On Mon, Jul 28, 2008 at 11:50 PM, Neil Mitchell <ndmitchell at gmail.com>wrote:

> Hi
> >> 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.
> I think SYB would best be maintained by someone who does not already
> maintain some kind of boilerplate removal library. There are lots of
> experiments into GADT's and other mechanisms, but SYB1+2 is a very
> useful design point - and one that should be preserved.

I agree that SYB1+2 is a useful design point and that improvements should
not affect the basic functionality and design. A library with a different
gfoldl would very likely change SYB significantly. However, I don't think
that there is a problem with a person maintaining several generic
programming libraries, as long as the maintainer effects
changes/improvements on SYB conservatively.

I think the
> maintainer should do three things in addition to general release
> management:
> 1) Speed improvements, if possible
> 2) API tweaks, maybe a few extra functions (universe equivalent would be
> nice)
> 3) Make it work with Hugs - I've always been surprised that SYB
> doesn't work with Hugs, and I don't think its that much work.
> As a result of these points, I think Claus is probably the perfect
> person to take over as maintainer.
> > (a) it helps to have someone else to "blame"
> > when the consequences of gfoldl's type once again hurt my brain;-),
> You can still blame those that went before - I don't think an SYB
> maintainer should be changing the type of gfoldl - its too
> fundamental.
> > (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 am interested. I have starred your emails, and will respond in the
> next few days. I've been in a tent without electricity for the last
> few days!

I would be fine with Claus as maintainer. As Johan mentioned, there are also
people in Utrecht who are interested in contributing with development or
even willing to take over maintainership if necessary. Probably it is best
to let Johan&co say more on Thursday :).

On a personal note, I prefer to not volunteer as a maintainer of SYB since I
have other personal priorities at the moment (focus on writing thesis,
searching for jobs), which also explains my slow reactions to emails.


-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.haskell.org/pipermail/generics/attachments/20080729/6569f78c/attachment-0001.htm

More information about the Generics mailing list