[Haskell-cafe] IO Monad

[yin]

Dinh Tien Tuan Anh wrote:

>
> Hi,
> Could anyone explain for me why its not possible to return a primitive
> type (such as Integer, String) while doing some IO actions ?
>
> e.g: foo :: IO() -> String
>
> What does it have to do with "lazy evalution" paradigm ?
>
In short, to not break functional aproach. Non-IO functions can't call
IO functions, because IO functions are evaluated every time you call them.

Matej 'Yin' Gagyi