On 11/26/20 12:07 PM, Guido van Rossum wrote: > This reminds me of something in C++. Does it exist in other languages? > A key point is that C++ needs 'move' behavior as its variables are buckets of bits, and assigning one variable to another, like in a call, requires copying that whole bucket of bits, and if it refers to other buckets of bits, may need to copy them too.
One thing that can be done when making this assignment, if the original isn't going to be needed is to 'steal' those buckets that the first object pointed to, possibly saving a lot of work. Python doesn't need to do this, as it isn't based on a bucket of bits type model, but its names are just bound to objects, and can readily share. Another way to think of the issue is it is mostly an issue with using Call By Value, which is the basic way to pass parameters in C and C++ (there is also a 'Call By Reverence' which is really just a Call by Value, where the value is a pointer, maybe with syntactic sugar to hide the pointerness) Python doesn't use Call by Value, but its method is better described as Call by Binding, the parameters in the function are bound to the pbjects specified in the call. If those objects are mutable, the function can change the object that the caller gave, but can't 'rebind' any variable names in the call statement to new objects. -- Richard Damon _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/5VKCC6OIDEFX74UUYAA77RZR4KJREUO4/ Code of Conduct: http://python.org/psf/codeofconduct/
