On Apr 26, 10:56 pm, "OKB (not okblacke)" <brennospamb...@nobrenspambarn.net> wrote: > Adam Skutt wrote: > > If I write a function that does a value comparison, then it should > > do value comparison on _every type that can be passed to it_, > > regardless of whether the type is a primitive or an object, whether > > it has value or reference semantics, and regardless of how value > > comparison is actually implemented. If I write some function: > > f(x : T, y : U) => x == y > > where T and U are some unknown types, then I want the function to > > do a value comparison for every type pairing that allows the > > function to compile. Likewise, if I write a function that does > > identity comparison, then it logically wants to do identity > > comparison on _every type that can be passed to it_. > > What you say here makes perfect sense, but also shows that you > really shouldn't be using Python if you want stuff to work this way. In > Python any value of any type can be passed to any function. The claims > you are making about object identity and object equality are reasonable, > but as you show here, to really handle them requires dragging in a huge > amount of type-system baggage.
So the check gets deferred to runtime, and the programmer may need to explictly throw 'NotImplemented' or something like that. Which is what happens in Python. Not type-checking arguments simply moves the burden from the language to the programmer, which is a standard consequence of moving from static to dynamic typing. Adam -- http://mail.python.org/mailman/listinfo/python-list
