Is FPH implemented in GHC?

Sittampalam, Ganesh ganesh.sittampalam at
Wed Sep 10 10:32:21 EDT 2008

I don't have a specific application that's crying out for this, but I
sometimes shy away from using higher-rank polymorphism because of the
extra effort it can require.

A possibly related question is whether you would expect to make record
selectors and updaters work for all record types at the same time? That
would definitely be very useful.

-----Original Message-----
From: glasgow-haskell-users-bounces at
[mailto:glasgow-haskell-users-bounces at] On Behalf Of Simon
Sent: 10 September 2008 15:25
To: Wolfgang Jeltsch; glasgow-haskell-users at
Cc: Dimitrios Vytiniotis (t-dimitv at
Subject: RE: Is FPH implemented in GHC?

Not yet.  But Dimitrios has just started a postdoc at MSR, so we will be
working on fixing, once and for all, the impredicative story in GHC.

Meanwhile, why do you ask?  Making impredicative polymorphism work seems
to be the Right Thing, but it's something of a "technology push",
perhpas a solution in search of a problem.  Do you have an application
that needs it?

This is a general question to GHC users.  (If you don't know what
impredicative polymorphism is, think "can I have a type like (Maybe
(forall a. [a] -> [a]))".)


| -----Original Message-----
| From: glasgow-haskell-users-bounces at 
| [mailto:glasgow-haskell-users- bounces at] On Behalf Of 
| Wolfgang Jeltsch
| Sent: 10 September 2008 15:21
| To: glasgow-haskell-users at
| Subject: Is FPH implemented in GHC?
| Hello,
| is FPH implemented in GHC?  If yes, will it be part of GHC 6.10.1?
| Best wishes,
| Wolfgang
| _______________________________________________
| Glasgow-haskell-users mailing list
| Glasgow-haskell-users at

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