[Python-Dev] PEP 550 v4

[Barry Warsaw]

I agree with David; this PEP has really gotten to a great place and the new organization makes it much easier to understand.

> On Aug 25, 2017, at 22:19, Ethan Furman <ethan at stoneleaf.us> wrote:
> 
> Why "lookup" and not "get" ?  Many APIs use "get" and it's functionality is well understood.

I have the same question as Sven as to why we can’t have attribute access semantics.  I probably asked that before, and you probably answered, so maybe if there’s a specific reason why this can’t be supported, the PEP should include a “rejected ideas” section explaining the choice.

That said, if we have to use method lookup, then I agree that `.get()` is a better choice than `.lookup()`.  But in that case, would it be possible to add an optional `default=None` argument so that you can specify a marker object for a missing value?  I worry that None might be a valid value in some cases, but that currently can’t be distinguished from “missing”.

I’d also like a debugging interface, such that I can ask “context_var.get()” and get some easy diagnostics about the resolution order.

Cheers,
-Barry

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