[Haskell-cafe] Haskell type system and the lambda cube

Petr Pudlak deb at pudlak.name
Sun May 24 04:39:50 EDT 2009

On Sun, May 24, 2009 at 12:18:40PM +0400, Eugene Kirpichov wrote:
> Haskell has terms depending on types (polymorphic terms) and types
> depending on types (type families?), but no dependent types.

But how about undecidability? I'd say that lambda2 or lambda-omega have
undecidable type checking, whereas Haskell's Hindley-Milner type system is
decidable. From this I get that Haskell's type system can't be one of the
vertices of the cube.

(BWT, will some future version of Haskell consider including some kind of
dependent types?)


> 2009/5/24 Petr Pudlak <deb at pudlak.name>:
> > Hi, I'm trying to get some better understanding of the theoretical foundations
> > behind Haskell. I wonder, where exactly does Haskell type system fit within the
> > lambda cube? <http://en.wikipedia.org/wiki/Lambda_cube>
> > I guess it could also vary depending on what extensions are turned on.
> >
> >    Thanks, Petr
> > _______________________________________________
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> >
> -- 
> Eugene Kirpichov
> Web IR developer, market.yandex.ru

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