Records in Haskell

Greg Weber greg at
Tue Jan 10 03:07:41 CET 2012

On Mon, Jan 9, 2012 at 2:22 PM, Isaac Dupree <ml at
> wrote:

> You mean this wiki page, right?:
>  That is, there are no fundamental
>> objections to the implementation of this records implementation.
> I think that might be overly optimistic... I think there's a risk that SPJ
> finds an irritating complication to type inference & the rest of us aren't
> type-system-savvy enough to continue trying to guess at that :) But I think
> you're referring to whether we object to ad-hoc overloading of record field
> names (neither parametric nor class-based polymorphism), if no difficulties
> crop up.  Some of the concerns on**haskellwiki/**
> TypeDirectedNameResolution<>apply -- I'm not sure to what extent, but address those concerns rather
> than require those people to repeat themselves again! :)
> (If we dodge all those obstacles, well, a better record system is better!)
This shouldn't complicate type inference (other than the fact that we must
avoid a left-right bias?) because the record field names are not overloaded
- instead it puts some burden back on the user to add more type
annotations. The difficult aspect of TDNR was that it was assuming
overloading - although there is really no reason why it can't instead
assume name-spacing. TDNR and this record proposal share many of the same
syntax issues you list. Thanks for the detailed feedback! I am travelling
right now, will review when I get a chance.

Greg Weber
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