[Python-ideas] PEP draft: context variables
Koos Zevenhoven
k7hoven at gmail.com
Tue Sep 5 09:53:52 EDT 2017
On Tue, Sep 5, 2017 at 1:20 AM, Oleg Broytman <phd at phdru.name> wrote:
> Hi!
>
> On Tue, Sep 05, 2017 at 12:50:35AM +0300, Koos Zevenhoven <
> k7hoven at gmail.com> wrote:
> > cvar = contextvars.Var(default="the default value",
> > description="example context variable")
>
> Why ``description`` and not ``doc``?
>
>
Cause that's a nice thing to bikeshed about? In fact, I probably should
have left it out at this point.
Really, it's just to get a meaningful repr for the object and better error
messages, without any significance for the substance of the PEP. There are
also concepts in the PEP that don't have a name yet.
> > with cvar.assign(new_value):
>
> Why ``assign`` and not ``set``?
>
To distinguish from typical set-operations (setattr, setitem), and from
sets and from settings. I would rather enter an "assignment context" than a
"set context" or "setting context".
One key point of this PEP is to promote defining context variable scopes on
a per-variable (and per-value) basis. I combined the variable and value
aspects in this concept of Assignment(variable, value) objects, which
define a context that one can enter and exit.
> > Each thread of the Python interpreter keeps its on stack of
>
> "its own", I think.
>
That's right, thanks.
––Koos
--
+ Koos Zevenhoven + http://twitter.com/k7hoven +
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