[Python-3000] PEP 3101 Updated

[Talin]

Eric Smith wrote:
> Talin wrote:
>> Eric Smith wrote:
>>> James Thiele wrote:
>>>> The section on the explicit conversion flag contains the following 
>>>> line:
>>>>
>>>>       These flags are typically placed before the format specifier:
>>>>
>>>> Where else can they be placed?
>>>
>>> I'd like this to say they can only be placed where the PEP describes 
>>> them, or maybe to be only at the end.
>>> "{0!r:20}".format("Hello")
>>> or
>>> "{0:20!r}".format("Hello")
>>>
>>> Putting them at the end makes the parsing easier, although I grant 
>>> you that that's not a great reason for specifying it that way.  
>>> Whatever it is, I think there should be only one place they can go.
>>
>> Guido expressed a definite preference for having them be first.
> 
> I was afraid of that.  Then can we say they'll always go first?  Or is 
> the intent really to say they can go anywhere (PEP says "typically 
> placed")?

I can revise it to say that they always come first if that's would make 
it easier.

> The sample implementation of vformat in the PEP says they'll go last:
> 
>               # Check for explicit type conversion
>               field_spec, _, explicit = field_spec.partition("!")

That's a bug.

Too bad there's no unit tests for pseudo-code :)

-- Talin