On Dec 7, 2007 7:57 PM, Luke Palmer <[EMAIL PROTECTED]> wrote: > On Dec 7, 2007 7:41 PM, Dan Weston <[EMAIL PROTECTED]> wrote: > > Luke Palmer wrote: > > > You can project the compile time numbers into runtime ones: > > > > Yes, that works well if I know a priori what the arity of the function > > is. But I want to be able to have the compiler deduce the arity of the > > function (e.g. by applying undefined until it is no longer a function), > > precisely so I don't have to supply it myself. > > > > Function arity is (I think) something already known to GHC, so I don't > > know why we can't get at it too. > > No, it is not. Consider: > > compose f g x = f (g x) > > What is the arity of f?
Oh, you're saying at run-time, given an object. Still no, by some definition. compose f g = f . g compose' f g x = f (g x) Are you saying that these two exactly equivalent functions should have different arity? If not, then is the arity 2 or 3? Luke _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
