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

Neil Mitchell ndmitchell at gmail.com
Tue Jun 3 17:23:02 EDT 2008


>> I was referring to base as "the set of Core libraries" - my
>> terminology was wrong, but my arguments were written with me thinking
>> "containers", so still apply.
> You arguments suggest that every module should be in a separate
> package.  In my experience this is a bad idea.

I think that any brand new module being proposed for the Core
libraries should first be available as a package, and then integrated
into the Core libraries afterwards. I think the barrier for getting
things in the Core libraries should be much higher. For non-Core
libraries, I would advocate grouping modules by functionality into
packages - but for non-Core libraries people are free to do whatever
they want :-)

>> Talking to people on IRC today it appears there is a reasonably large
>> design space for a zipper interface. If this is true, then putting a
> Could you elaborate on this?  What are the different design choices
> that your IRC discussions revealed?

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

>> I think that's a real shame. Maintaining a cabal package is relatively
>> little effort. I have several packages which are just one module long
> Mico-managing a slew of different packages is a pain, especially if
> you are actually serious about maintaining the packages.  It also
> makes finding packages and keeping track of the dependencies between
> them hard---cabal-install only helps with downloading the right
> packages, and it is not always an option to use it.

If you have a package for every single module, then yes. If not, then
its not that bad. Yes, you need some more infrastructure, but Cabal
provides most of it. Maintaining a zipper package for a few months
really wouldn't be that much work.



More information about the Libraries mailing list