On Sat, May 10, 2014 at 12:19 PM, Rustom Mody <rustompm...@gmail.com> wrote: > For me, Marko's comment that variables in python are not first-class > whereas in C they are is for me the most important distinction Ive seen > (in a long time of seeing these discussions). >
https://en.wikipedia.org/wiki/First-class_citizen For variables in C to be considered first-class, they must, by most definitions, be able to be passed around as parameters and return values. Some definitions also require that they be able to be constructed at run-time. How do C variables shape up? 1) Passing them as parameters. You can pass a pointer to a variable, which is effectively the same as passing a variable to a function. The callee can mutate your variable through the pointer. 2) Returning them. This is a lot more dodgy, owing to the dangling-pointer issue, but as long as you accept that the reference to a variable doesn't ensure its continued life, I suppose this might be acceptable. Maybe. But it's pushing it. 3) Constructing at run-time. Really REALLY pushing it. You can malloc and call that a "variable", but it's not a variable any more, it's just a patch of memory. In fact, all this proves is that variables represent patches of memory, and patches of memory are first-class. Not liking the results here. You might just as well define that all Python variables must be backed by a dictionary (it's just as true as "all C variables must be backed by memory") and then define the first-class-variable as a combination of a dict and a key. ChrisA -- https://mail.python.org/mailman/listinfo/python-list