You mention NFData in the motivation but then say that !Maybe !Int is not allowed. This leads me to wonder what the semantics of foo :: !Maybe Int -> !Maybe Int foo x = x bar = foo (Just undefined) are. Based on the FAQ it sounds like foo would *not* force the undefined, is that correct? Also, there's a clear connection between these UnliftedTypes and BangPatterns, but as I understand it the ! is essentially a new type constructor. So while foo1 :: !Int -> !Int foo1 x = x and foo2 :: Int -> Int foo2 !x = x have the same runtime behavior, they have different types, so you can't pass a regular Int to foo1. Is that desirable? Eric On Fri, Sep 4, 2015, at 01:03, Edward Z. Yang wrote:
Hello friends,
After many discussions and beers at ICFP, I've written up my current best understanding of the unlifted data types proposal:
https://ghc.haskell.org/trac/ghc/wiki/UnliftedDataTypes
Many thanks to Richard, Iavor, Ryan, Simon, Duncan, George, Paul, Edward Kmett, and any others who I may have forgotten for crystallizing this proposal.
Cheers, Edward _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs