On Tue, 18 Dec 2007, Benja Fallenstein wrote: > Hi Cristian, > > On Dec 18, 2007 10:53 AM, Cristian Baboi <[EMAIL PROTECTED]> wrote: > > >> - the lambda expressions can be written (input) but cannot be printed > > >> (output) > > > > > Yes, since two different lambda expressions can denote the same function. > > I just want the sistem to be able to print one of these expressions ! > > > > Its this too much to ask ? > > I find it very strange that I can write a lambda expresion, but the system > > cannot. > > It's a trade-off. Haskell has as a design goal that you can use > equational reasoning everywhere -- that if you have two ways of > writing the same function, you can substitute one for the other in any > expression, without changing the result of that expression. For > example, since you can prove > > sum = foldl (+) 0 = foldr (+) 0 = last . scanl (+) 0
Since this was discussed already here, I summed it up in: http://www.haskell.org/haskellwiki/Show_instance_for_functions _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
