[Haskell-cafe] Records

Greg Woodhouse gregory.woodhouse at sbcglobal.net
Tue Nov 22 13:30:05 EST 2005

--- Sven Panne <Sven.Panne at aedion.de> wrote:

> I think this discussion has reached a point where it is of utmost
> importance 
> to re-read "Wadler's Law of Language Design", a law so fundamental to
> computer science that it can only be compared to quantum dynamics in
> physics:
>    http://www.informatik.uni-kiel.de/~mh/curry/listarchive/0017.html
> :-)
> Cheers,
>    S.

To be honest, I haven't followed the entire records thread (at least
not yet), but I don't know that it's fair to say that we've been
focusing entirely (or nearly so) on lexical issues. I'll grant you that
there's an awful lot of that going on, but unless I'm missin something
obvious, support for a record data type isn't even a purely syntactic
issue. If records are to be supported, they need to have semantics, and
it's not obvious to me how this is to be done in a functional language.

That being said, this is a matter of some interest to me, primarily
because I've been thinking about how to go about using Haskell with
(not necessarily relational) databases, and it seems awkward to use a
tuple or heterogenous list in a context where new attributes can be
added to existing data. Now, of course, that's a puzzle in it's own
right: How on earth can you achieve anything like referential
transparency here? 

Gregory Woodhouse  <gregory.woodhouse at sbcglobal.net>

"Interaction is the mind-body problem of computing."

--Philip Wadler

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