[Haskell-cafe] Re: [Haskell] Re: Re: RE: Extensible records: Static duck typing

[Mark P Jones]

[Redirecting to haskell-cafe]

Ben Franksen wrote:
> TREX seems to be generally agreed to be too complicated to implement and
> explain.

What evidence do you have for this?  Speaking as somebody who
implemented Trex for Hugs (and who also witnessed Ben Gaster
build an independent implementation), I'd have to disagree
about the first part of this.  As I recall, the implementation
was reasonably straightforward, and wasn't any more complicated
than other common type system extensions that I've worked on.
I'm also not sure why you think it is complicated to explain,
but I suppose that's even more subjective.

One of the most difficult things about the Trex implementation
was finding a syntax that meshed nicely with the rest of the
Haskell syntax.  This is likely to be a problem for any record
system extension of Haskell---unless you're prepared to accept
a more unconventional syntax---because many of the symbols that
you might want to use ({, }, ., |, \, for example) have already
been adopted for other purposes.  Ah, syntax!

All the best,
Mark