Rob Cliffe wrote:
But when a frozen list a.k.a. tuple would be created - either directly, or by setting a list's mutable flag to False which would really turn it into a tuple - the size *would* be known.
But at that point the object consists of two memory blocks -- one containing just the object header and a pointer to the items, and the other containing the items. To turn that into a true tuple structure would require resizing the main object block to be big enough to hold the items and copying them into it. The main object can't be moved (because there are PyObject *s all over the place pointing to it), so if there's not enough room at its current location, you're out of luck. So lists frozen after creation would have to remain as two blocks, making them second-class citizens compared to those that were created frozen. Either that or store all lists/tuples as two blocks, and give up some of the performance advantages of the current tuple structure. -- Greg _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
