On 10/25/07, Matej Kosik <kosik at fiit.stuba.sk> wrote:
> I am sorry. This wasn't the proper word.
>
> Certainly, I believe that there are things that cannot be modelled in the pure functional language
> (whose constructs can be without exceptions mapped to the lambda-calculus). This is not only the
> case of input/output. This is also the case of modelling stateful systems that interact with their
> environment over time (not only at the beginning and at the end). So pretending that functional
> programming can cover all the important aspects of systems we need to model is unfaithful. Those
> impurities are useful.

Um, you are aware that lambda-calculus is Turing equivalent right?

http://en.wikipedia.org/wiki/Turing-complete

"The untyped lambda calculus is Turing-complete, but many typed lambda
calculi, including System F, are not."