[Python-ideas] Show deprecation warnings in the interactive interpreter

[Chris Angelico]

On Wed, Feb 25, 2015 at 9:01 PM, Ben Finney <ben+python at benfinney.id.au> wrote:
> Steven D'Aprano <steve at pearwood.info> writes:
>
>> On Wed, Feb 25, 2015 at 07:39:50PM +1100, Ben Finney wrote:
>> > To its detriment: Making the interactive interpreter behave differently
>> > by default from the non-interactive interpreter should be resisted; code
>> > which behaves a certain way by default in one should behave the same way
>> > in the other, without extremely compelling justification.
>>
>> The ship has sailed on that one. […]
>
> Please note two things:
>
> I don't claim there must be no differences, only that differences
> proposed today must come with compellign justification.
>
> The fact that there are already differences doesn't justify diverging
> further. Whatever positive justification is offered, “they already
> diverge” cannot count for creating further divergence.

Agreed; the difference does need justification. Here's justification:
Interactive execution places code and output right next to each other.
The warning would be emitted right at the time when the corresponding
code is entered.

Hmm. There are a few places where code gets pre-evaluated by the back
end (eg to figure out whether a continuation prompt is needed). Should
applicable SyntaxWarnings be emitted during such partial evaluation,
or should they be held over until the whole block can be parsed?

ChrisA