getChar is a Haskell function without arguments.
http://hackage.haskell.org/package/base-4.11.1.0/docs/Prelud...
It represents an interaction with the outside world that results in a Char when you perform it. It isn't a function because in Haskell functions must be pure (with no side effects).
From your other post: "In both Gluon and Haskell, functions without arguments can be represented as functions over the unit type: f: () -> SomeType"
Isn't `f` a constant here too?, how is this different than getChar? (I get I don't understand something here but not sure what)
(Though yes, `f` also is a constant... it's just a constant that happens to be a function, which `getChar` is not.)
data MyFun a = MyFun (() -> Char)