[Haskell-cafe] Re: Can we come out of a monad?

[Steve Schafer]

On Tue, 10 Aug 2010 18:27:49 -0300, you wrote:

>Nope.  For example, suppose we have:
>
>  int randomNumber(int min, int max);
>
>Equivalentely:
>
>  randomNumber :: Int -> Int -> IO Int
>
>In Haskell if we say
>
>  (+) <$> randomNumber 10 15 <*> randomNumber 10 15
>
>That's the same as
>
>  let x = randomNumber 10 15
>  in (+) <$> x <*> x
>
>If we had in C:
>
>  return (randomNumber(10, 15) + randomNumber(10, 15))
>
>That would not be the same as:
>
>  int x = randomNumber(10, 15)
>  return (x + x)

I think you're misinterpreting what Martijn is saying. He's not talking
about referential transparency at all. What he's saying is that in a
language like C, you can always replace a function call with the code
that constitutes the body of that function. In C-speak, you can "inline"
the function.

-Steve