Re: Generative record types

[William D Clinger <will@ccs.neu.edu>]

> B. Type inference.  Why not add a type facility to the record
>    proposal?
> 
>    For example, you could qualify each field with a predicate that the
>    corresponding components must satisfy.  The mutators generated
>    could then check and guarantee no inconsistencies.

I don't think this is likely to work.  How would you construct
a predicate for the following type?

  forall (a, b)  (a * (a -> b)) -> b

This is hardly an esoteric example, since it is the type that
would be inferred for

  (lambda (x f) (f x))

Will