Re: [Haskell-beginners] How to avoid repeating a type restriction from a data constructor

25 Apr 2013

      Daniel Fischer  writes:
...
...
You've mentioned GADT a few times, but I can't find a case where it's
different to regular datatypes.

data Foo a = Eq a => Foo a

seems to have the same effect as

data Foo a where
   Foo a :: Eq a => a -> Foo a

Both remember the Eq constraint if I pattern match on the constructor, and
both ignore it otherwise.

Re: [Haskell-beginners] How to avoid repeating a type restriction from a data constructor

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