Higher rank types

[Simon Peyton-Jones]

Dear Haskellers

For a long time now, Mark Shields and I have been writing a paper
describing GHC's approach to type inference for higher-rank types.
We've finally finished a complete draft:

	Practical type inference for arbitrary-rank types=20
	Simon Peyton Jones and Mark Shields
	http://research.microsoft.com/~simonpj/papers/putting/index.htm

The paper has a strongly tutorial flavour, and comes complete with a
prototype implementation that you can play with.  My hope is that, in
addition to describing higher-rank stuff, the paper may serve as a kind
of tutorial on type inference generally, and the use of monads to
support the plumbing in particular.  There's nothing really new about
this aspect of the paper, but I don't know of a comparable tutorial that
takes a monadic approach.

It's still very much a draft, so I'd be very interested in your feedback
about it.

Simon