Re: [Haskell-cafe] Docs on the current and future constraint solver?

On Wed, Jul 14, 2010 at 4:42 PM, Thomas Schilling wrote:

The latest work is OutsideIn(X):  http://www.haskell.org/haskellwiki/Simonpj/Talk:OutsideIn

This is quite long paper.  It describes a framework for constraint-based type inference and then instantiates it with a constraint solver that supports type families, GADTs and type classes.

Sounds like it's a long paper with good reason ;-) I will start working my way through it. Thanks for the information. Cheers, Corey O'Connor

On 14 July 2010 18:39, Corey O'Connor wrote:

...

I believe I have run headlong into issue #3064 in ghc (http://hackage.haskell.org/trac/ghc/ticket/3064). All I think I know is this: * this is a performance issue with the system used to solve type constraints. * the solver is undergoing an overhaul to resolve performance issues in addition to other issues. * An efficient constraint solver is difficult. NP-Complete in the general case?

Beyond that I'm at a loss. What can I read to understand the constraint satisfaction problem as it stands in GHC? Is there a paper on the implementation of the current solver? Anything on how the new solver will differ from the current?

I think I located one page on the new solver: http://hackage.haskell.org/trac/ghc/wiki/TypeFunctionsSolving

Cheers, Corey O'Connor _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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