Steven D'Aprano wrote: > On Sun, 04 Jan 2009 20:03:11 -0600, Derek Martin wrote: [...]>>>> And for that matter, it's pretty unintuitive generally. >>> Names and objects are quite "natural" IMHO. There are many real world >>> objects which we attach one or more names to, or refer to in sequences >>> like "please give me the third book on that shelve" (``shelve[2]``). >> Indeed, but the way we assign names to them does not behave as it does >> in Python. > > It doesn't? > > Oh my, you're going to be confused in a few weeks when The President of > the USA ceases to be George W Bush and becomes Barack Obama. Same name > (or rather, title), different object (person). > No, he will doubtless describe the White House as a President variable whose value has been overwritten. There are many fine jokes to be made about the need to garbage-collect President Bush ... > > >> Nor does Python's assignment work like it does in algebra, > > Nor does any programming language, with the possible exception of > computer algebra systems. > I'm still waiting for an explanation of where assignment comes into algebra in the first place. > [...] > >> Those interpretations came first, because, much as in the >> evolution of any other science, that was the model which was most >> intuitive or easily explained. > > No no no no. That was the model that was most easily implemented! > Agreed. In those days the von Neumann architecture was a shiny new thing, and it was even a while before people thought of using computers for symbolic rather than numeric operations (which is IMHO what makes them so interesting).
> Before the named bins model of assignment was pure machine code, where > you didn't have bins at all, just bits, and there was no distinction > between code and data. And before that was *wires* -- early programmers > literally had to plug and unplug wires to change the state of the > computer. And before that were purely mechanical devices, such as the > Enigma Machine, old calculators, and the grand-daddy of them all, Charles > Babbage's difference engine and it's precursors. > Aah, the old Univac 1004. Sorry, I'm rambling. > > >> But you need not take my word for it. Simply read the archives and see >> for yourself how much confusion this has caused on this list. [Please >> include the closely related behavior of parameter passing in your >> search.] > > In my opinion, the cause of that confusion is nothing to do with Python's > assignment model, and everything to do with the instance of some people > to use named bins terminology when describing the Python model. If you > keep the named bins terminology for describing the named bins model, > you're fine; and if you keep the name/object terminology for describing > languages with names/objects, you're fine. You only run into trouble when > you mix them. That's when you get people confused because "Python is Call > By Something, but it doesn't behave like Call By Something in language > Foo I've used before". > > This really does go to show that (some) people will argue about anything, with the major intention of proving themselves right rather than reaching a common understanding. regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
