Re: Why are functors better? (Re: [Caml-list] Map efficiency?)

[Michael Hicks <mwh@cs.umd.edu>]

Benjamin Pierce did a nice talk at ICFP a couple of years ago about
sophisticated module systems, examining where (or if) they are really
needed.  The slides are at

http://www.cis.upenn.edu/~bcpierce/papers/modules-icfp.ps

This is not exactly on target for your point about ease-of-use, but it's
related.
Mike


On Fri, 2003-11-07 at 06:39, Yaron M. Minsky wrote:
> On Fri, 2003-11-07 at 03:27, Jean-Christophe Filliatre wrote:
> > [ Some discussion of methods for building maps without functors ]
> >
> > (But the functorial interface is definitely the best, of course.)
> 
> I don't understand this perspective at all.  Functors seem like a fairly
> problematic corner of the language.  In this case, except for some
> possible efficiency issues, it seems clear that a non-functorial map is
> preferable, for simplicity and ease-of-use issues, and performance
> aside, I can't see much to recommend the current functorial approach.
> 
> Functors would be a lot more useful if they could be used as a
> large-scale structural tool.  Sadly, the current implementation makes
> this quite difficult, since there's no good way of parameterizing
> multiple modules at once (as noted in a previous thread.  See
> 
> http://groups.google.com/groups?q=group%3Afa.caml+functors+yminsky&ie=UTF-8&oe=UTF-8&hl=en&btnG=Google+Search
> 
> for details.)  For most situations where you'd really need them, they're
> not powerful enough.  And for the situations where they're powerful
> enough, they're usually overkill.  Map and Set are examples where they
> almost strictly get in the way.
> 
> y
-- 
Michael Hicks <mwh@cs.umd.edu>

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