> It's possible that there's some more direct approach that > represents types as some kind of runtime values, but nobody > (to my knowledge) has done that.
It don't think its possible - I tried it and failed. Consider: show (f []) Where f has the semantics of id, but has either the return type [Int] or [Char] - you get different results. Without computing the types everywhere, I don't see how you can determine the precise type of []. Thanks Neil > On Wed, Nov 12, 2008 at 12:39 PM, Luke Palmer > <[EMAIL PROTECTED]> wrote: > > On Wed, Nov 12, 2008 at 3:21 AM, Jules Bean > <[EMAIL PROTECTED]> wrote: > >> 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. > > > > Haskell 98 does not seem that big to me (it's not teeny, but it's > > nothing like C++), yet we are continually embarrassed about > not having > > any formal semantics. What are the challenges preventing its > > creation? > > > > Luke > > _______________________________________________ > > Haskell-Cafe mailing list > > Haskell-Cafe@haskell.org > > http://www.haskell.org/mailman/listinfo/haskell-cafe > > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > > ============================================================================== Please access the attached hyperlink for an important electronic communications disclaimer: http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html ============================================================================== _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe