On 26/07/2019 08:13, Batuhan Taskaya wrote:
I am proposing namespace context managers with implementing `__enter__` and
`__exit__` on dict objects.
Didn't we have this discussion recently? What do these __enter__() and
__exit__() do? Please don't answer with an example, I want to
understand what this mechanism is supposed to achieve.
Also, I can't tell if you're proposing to add __enter__ and __exit__ to
dict objects or have the "with" statement magically add them. Is it
just dicts, or will any mapping type do?
It would make closures possible in python with
a pythonic syntax.
a = 4
namespace = {}
with namespace:
a = 3
assert a == 4
assert namespace["a"] == 3
Right, so it's in effect supplying a different dictionary for local
variables. How do these stack? Innermost namespace takes priority?
Are outer namespaces accessible using nonlocal? How does this interact
with other sorts of namespaces?
I don't think dicts are the right place to start. I think you want a
specialised namespace object that supplies a mapping interface. That
gives you a lot more flexibility when it comes to implementation,
amongst other things.
(I'm not actually very keen on namespaces like this, personally. Too
much debugging of C++ code has made me very twitchy about unstructured
names. That's besides the point, though.)
--
Rhodri James *-* Kynesim Ltd
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