5 Feb
2009
5 Feb
'09
11:18 a.m.
On Thu, Feb 5, 2009 at 9:53 AM, Gleb Alexeyev
Let's imagine that IO datatype is defined thus:
{-# LANGUAGE GADTs #-} {-# LANGUAGE NoImplicitPrelude #-}
import Prelude(Monad, Char) data IO a where GetChar :: IO Char Bind :: IO a -> (a -> IO b) -> IO b
getChar = GetChar (>>=) = Bind
It is perfectly possible to construct IO actions as values of this data type and execute them by some function evalIO :: IO -> Prelude.IO with the obvious definition. Now the question arises: do you think getChar >>= \x -> getChar would be optimized to getChar by compiler?
I must be misunderstanding something. I don't know if it would be optimized out, but I see no reason why it couldn't be. There's no data dependency, right? -g