为什么没有数据构造函数的类型有效？

Question

This seems to be legal:

data MagazineInfo = Int String
    deriving (Show)

I am not sure if there is a default data constructor, but the above code compiles.

Why is the above valid Haskell, since I did not explicitly specify a value constructor?

Answer 1

You do have a data constructor there--it's Int . Type names live in a separate namespace from data constructors, which is why you don't get an error even though there happens to be a type also named Int .