[Haskell-cafe] semantics of type synonym

pbrowne Patrick.Browne at comp.dit.ie
Tue Dec 29 09:47:55 EST 2009

I am studying the underlying semantics behind Haskell and to what degree
those semantics are actually implemented. I need to clarify what a *type
synonym* actual means in relation to Haskell's logic (or formal
semantics). I used the following type synonym:

type Name = String
getName(n) = n

I checked the types with two tests:
-- test 1
:t "ww"
"ww" :: [Char]

-- test 2
:t getName("ww")
getName("ww") :: Name

Obviously I get two different types.
In the case of the function Haskells type system seems to pick up enough
information to determine that “ww” is a Name.
But I am not sure what is happening with the literal "ww" in the first test.


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