On Mon, Apr 6, 2009 at 10:09 PM, Eugene Kirpichov <[email protected]> wrote: > Since the argument to sortBy must impose a linear ordering on its > arguments, and any linear ordering may as well be generated by > assigning an integer to each element of type 'a', and your sorting > function is polymorphic, from the free theorem for the sorting > function we may deduce that it suffices to test your function on > integer lists with a casual comparison function (Data.Ord.compare), > and there is no need to generate a random comparison function.
Interesting. How is this free theorem stated for the sorting function? Intuitively I understand that if the type is polymorphic, then it seems reasonable to just pick one type and go with it. Thanks, Jason _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
