On Mon, 4 Aug 2003, Ashley Yakeley wrote: > At 2003-08-04 18:19, Ben Rudiak-Gould wrote: > > >> ((\a -> ((a,[EMAIL PROTECTED] -> @x) [EMAIL PROTECTED] = 2})) ([EMAIL PROTECTED] > >> -> @x),[EMAIL PROTECTED] -> @x) [EMAIL PROTECTED] = 1} > > ^^^ > >> (([EMAIL PROTECTED] -> @x,[EMAIL PROTECTED] -> @x) [EMAIL PROTECTED] = 2},[EMAIL > >> PROTECTED] -> @x) [EMAIL PROTECTED] = 1} > > > >This reduction is incorrect. > > It's a simple beta-reduction, it must be correct.
This is a different lambda calculus, with a different beta rule. You can see the same effect in the type inference rules for implicit parameters: If f has type Int -> String and ?x has type (?x :: Int) => Int, then f ?x has type (?x :: Int) => String, i.e. the implicit ?x parameter is lifted out of the RHS to become a parameter of the whole application node. This rule is what makes implicit parameters implicit. As you pointed out, this reduction behavior depends on f's type, so this is necessarily a typed lambda calculus. But that's okay because Haskell is statically typed. -- Ben _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
