Re: [Haskell-cafe] Proof that Haskell is RT

Andrew Birkett wrote:

Hi,

Is a formal proof that the Haskell language is referentially transparent? Many people state "haskell is RT" without backing up that claim. I know that, in practice, I can't write any counter-examples but that's a bit handy-wavy. Is there a formal proof that, for all possible haskell programs, we can replace coreferent expressions without changing the meaning of a program?

The (well, a natural approach to a) formal proof would be to give a formal semantics for haskell. Referential transparency would be an obvious property of the semantics. Soundness would show that it carried over to the language. Jules