Is FPH implemented in GHC?

Simon Peyton-Jones simonpj at
Mon Sep 15 08:05:35 EDT 2008

| Some of the trivial functions, I mentioned above, have rank 2 types, some have
| impredicative types.  The latter ones typically have types of the form
|     f (forall t. signal t a) -> f (forall t. signal' t a')
| where f is some specific functor.

Aha -- that's impredicative all right. Good thanks.

| And as far as I understood, FPH brings advantages for both rank n and
| impredicativity.  Am I wrong at this point?

No, you're right.


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