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

Ivan Miljenovic wrote:

On 2 August 2010 14:47, Lyndon Maydwell wrote:

...

I thought it was pure as, conceptually, readFile isn't 'run' rather it constructs a pure function that accepts a unique world state as a parameter. This might be totally unrealistic, but this is how I see IO functions remaining pure. Is this a good mental model?

That is what I believe Ertugrul is aiming at, but I believe that that is a "rule-lawyering" interpretation in trying to argue that all of Haskell is pure. We could use this same argument to state that _all_ programming languages are pure, as they too have implict "World" state variables that get passed around.

Given the definition of a Haskell function, Haskell is a pure language. The notion of a function in other languages is not: int randomNumber(); The result of this function is an integer. You can't replace the function call by its result without changing the meaning of the program. In Haskell, this wouldn't even be a function. It would be a computation, i.e. simply a value. Greets, Ertugrul -- nightmare = unsafePerformIO (getWrongWife >>= sex) http://ertes.de/