> So things like decimal.Context get left trying to find a sane
> name for what their __context__ method returns.
> decimal.Context.__context__() returns a . . . context? What?
> Wasn't it already a context? Oh, so it actually returns a
> "with statement context object".
[I was OK with "context specifiers", but here is another attempt.]
-----------
With statements execute in a temporary context.
with with_expression as temporary_context_name:
stmt1
stmt2
The with_expression must return an object implementing the Temporary
Context protocol. The Temporary Context's __enter__ method runs
before the statement block, and its __exit__ method runs after the
block.
Temporary Contexts can represent arbitrary changes to the execution
environment. Often, they just ensure that a file is closed in a
timely fashion.
A more advanced example is Decimal.Context, which controls the
precision of certain math calculations. Decimal.Context also
implements the Temporary Context protocol, so that you can increase
the precision of a few calculations without slowing down the rest of
the program.
-jJ
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