pbrowne wrote:
Hi, 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.
Wrong. You get exactly the same type, it's just that GHCi detected that you have a fancy name for this type, so it gives you that name. It's not type system, it's just GHCi.
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.
Pat
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