2009/12/6 Stefan Holdermans <ste...@cs.uu.nl>: > Eugene, > >> 1) Does there exist an authoritative source saying the same? Not that >> I'm doubting, just supposing that the source would have other >> interesting information, too :) > > You may want to have a look at the already mentioned JFP-article by Peyton > Jones et al. and perhaps the work of Kfoury and Wells. > >> 2) Is it true that rank (forall a . a, forall a . a) == 0 ? > > No, for pairs one takes the maximum of the constituent types. So, here you'd > get rank 1. > > Note that this is an impredicative type, which is yet another extension of > the standard Hindley-Milner typing discipline.
OK, thanks. However, isn't the type (forall a . a) -> String impredicative because it instantiates a type variable of the type constructor (->) p q with p = forall a . a? > > Cheers, > > Stefan >> >>> > -- Eugene Kirpichov Web IR developer, market.yandex.ru _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
