> It's because Python doesn't actually have assignment to variables, it > has binding to names. So there's no "there" there to provide a > definition of assignment. In a class definition, the "local > variables" are actually attributes of the class object. That class > object provides the "there", which in turn allows redefinition via a > metaclass.
I understand this and while I would love to have metamodules and metafunctions to provide me a 'there' that is for another thread. I don't really want to change the semantic of =. What Yanghao and I are asking for is an in-place update/assign operator which isn't burdened with numeric meaning. Caleb Donovick On Thu, Jun 13, 2019 at 1:42 PM Stephen J. Turnbull < turnbull.stephen...@u.tsukuba.ac.jp> wrote: > Caleb Donovick writes: > > > In class bodies it is easy to redefine what assignment means, in > > every other context its very annoying, I don't see why that must be > > the case. > > It's because Python doesn't actually have assignment to variables, it > has binding to names. So there's no "there" there to provide a > definition of assignment. In a class definition, the "local > variables" are actually attributes of the class object. That class > object provides the "there", which in turn allows redefinition via a > metaclass. > > Of course this doesn't *have* to be the case. But in Python it is. > AFAICS making assignment user-definable would require the compiler to > be able to determine the type of the LHS in every assignment statement > in order to determine whether name binding is meant or the name refers > to an object which knows how to assign to itself. I don't see how to > do that without giving up a lot of the properties that make Python > Python, such as duck-typing. > > Steve > >
_______________________________________________ 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/GCICN3H22DB4JNK23ZX4TMGYESNBTVS4/ Code of Conduct: http://python.org/psf/codeofconduct/
