Keep the present Haskell record system!

Ross Paterson ross at
Thu Mar 2 04:31:15 EST 2006

On Wed, Mar 01, 2006 at 11:00:41AM +0000, Malcolm Wallace wrote:
> Thus, although I agree that none is ready for inclusion in
> Haskell-prime, I think we do need some mechanism for experimental
> records to be tried out in real Haskell implementations before the
> Haskell-double-prime committee starts its work.
> Perhaps, taking the extensions-layering idea, we could say that the
> current named-fields are encapsulated as an "extension that is part of
> the standard".  Implementations could then introduce a flag to switch
> off this particular extension (current records) in conjunction with
> flags to switch on experimental replacements.  This would give a certain
> flexibility for users to play with different systems, and the breaking
> of compatibility would be explicitly notated, either by the build
> options, or using a proposal like ticket #94.
> My suggestion is that we separate out everything from the Report to do
> with named-field records into something like a self-contained addendum.
> Whilst still an official part of the language standard, it might also be
> marked as a possibility for future removal.  This would make it clear
> what parts of the language could be changed (or re-used without conflict)
> in an alternative records system.

Sounds like a good idea to me, if it can be done.  We might want to do
the same thing with FDs (assuming we come up with a form good enough
for Haskell').

There will be a question of how contagious these extensions are, e.g.
am I using extension X if I import a module that uses it?

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