[Haskell-cafe] Kind of confusing

Tue May 12 21:05:41 EDT 2009

On Tue, 2009-05-12 at 14:09 +0100, Philippa Cowderoy wrote:
> On Mon, 2009-05-11 at 20:43 -0400, Anton van Straaten wrote:
> > Serious question: what is the significance of the question mark and 
> > double question marks in those signatures, or better yet, where can I 
> > read about it?
> > 
> 
> I've forgotten where to find the details (try the GHC manual if you
> haven't already?), but IIRC they're part of how GHC handles boxing.
> 

http://hackage.haskell.org/trac/ghc/wiki/IntermediateTypes