Fwd: [Haskell-cafe] Data.Tree.Zipper in the standard libraries

[Don Stewart]

duncan.coutts:
> 
> On Wed, 2008-06-04 at 08:29 +0200, Krasimir Angelov wrote:
> > On Tue, Jun 3, 2008 at 11:23 PM, Neil Mitchell <ndmitchell at gmail.com> wrote:
> > > ndm> I was wondering if there is just one way to do a zipper?
> > > _other person_> I've done them using several different interfaces, I'm
> > > not quite sure which one I like best yet.
> > >
> > > (I know who _other person_ is, but it seems unfair to quote IRC with
> > > names back at people, given the instant and non-committal nature of
> > > IRC)
> > 
> > I would prefer the important discussions to be led not in IRC but in
> > the mailing list. I personally very rarely (almost never) go to
> > channel #haskell because I can't concentrate on my work if I have to
> > follow the endless discussions in the channel. By the way so far your
> > voice seems to be the only one against. I would like to hear what the
> > other guys think.
> 
> I would tend to agree with Neil that significant additions to the core
> libraries should be proven first as separate packages and integrated
> later.

I wonder if there's a good case already:

   The zipper module here has:

    * A solid theoretical foundation (its a straightforward derivative
      of a data type)

    * Sensible API derived from Huet's papers, then implemented and used
      for Yi, one of the larger Haskell projects

    * Rich testsuite -- with 100% test coverage

And its a derivative of a type in containers, so makes sense to be in
containers, no?

If not, maybe we need to clarify the process for inclusion in the core
lib set. E.g. the above constraints, and "6 months testing as a
standalone package"

-- Don