Raymond Hettinger wrote:
On Oct 21, 5:18 pm, Paul Rubin <no.em...@nospam.invalid> wrote:
The API you suggested looks reasonable although you should also say how
to delete a context, how to find the inner contexts of a context, etc.
The c.parent.parent.parent chain finds successive enclosing contexts:
while c.parent is not None:
print c
c = c.parent
One question: what should
c["foo"] = 7
d = c.new_child()
del d["foo"]
do?
By default, it raises a KeyError because 'foo' is not in the current
context.
But if enable_nonlocal is set to True, it removes 'foo' from the
parent context, c.
Depends on whether you want parent contexts to be mutable or not.
With Python's nonlocal keyword, we can set values in an enclosing
scope. This tool lets you do that also.
Another possibility would be to set d["foo"] to some sentinel value,
effectively blocking access to the parent's value. Of course, the user
could also do that, it need not be built-in to the nested-mapping.
~Ethan~
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