[Haskell-cafe] On to applicative
bulat.ziganshin at gmail.com
Tue Aug 31 13:41:03 EDT 2010
Tuesday, August 31, 2010, 9:27:17 PM, you wrote:
f :: Int -> Int
i.e. it's used when you define function types
> So it's a type constructor, not a type? Could you please provide a simple example of its usage?
> --- On Tue, 8/31/10, Vo Minh Thu <noteed at gmail.com> wrote:
> From: Vo Minh Thu <noteed at gmail.com>
> Subject: Re: [Haskell-cafe] On to applicative
> To: "michael rice" <nowgate at yahoo.com>
> Cc: haskell-cafe at haskell.org
> Date: Tuesday, August 31, 2010, 1:17 PM
> 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).
> 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.
Bulat mailto:Bulat.Ziganshin at gmail.com
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