Records in Haskell

AntC anthony_clayden at
Tue Feb 28 12:16:51 CET 2012

Greg Weber <greg <at>> writes:

> I looked at the DORF implementers view
> It appears that we still have no solution for record updates that
> change the type of a polymorphic field.

There's two varieties of polymorphic fields:
- the type-changing variety
  DORF has a solution for update/changing the type of field and record
             (always has since the proof of concept in December)
  SORF has a speculative suggestion of Quasifunctor
            (looks like this needs tightening up??)
- the higher-ranked variety
  neither proposal has a way of updating
             (well, DORF did but it's an unscalable "hack" [SPJ],
              I put it on the wiki anyway, in case somebody can improve it)


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