[Haskell-cafe] On to applicative

[Vo Minh Thu]

2010/8/31 michael rice <nowgate at yahoo.com>
>
> "Learn You a Haskell ..."  says that (->) is a type just like Either. Where can I find its type definition?

You can't define it *in* Haskell as user code. It is a built-in infix
type constructor (Either or Maybe are type constructors too, not just
types). In fact, if you want to implement a simple, typed functional
language, you'll find it is the only built-in type constructor you
have to implement (as the implementor of the language).

Also,
  Show a => a
is a type too, but you won't find a definition for 'a' or for '=>'.
All those things are defined by the language.

Cheers,
Thu