[Python-ideas] Briefer string format

[Mike Miller]

On 08/02/2015 07:43 PM, Eric V. Smith wrote:
> On 8/2/2015 7:46 PM, Mike Miller wrote:
>> I don't understand how we got to arbitrary expressions.
> I think here:
> https://mail.python.org/pipermail/python-ideas/2015-July/034701.html

In that message, GvR seems to be exploring the options.  I could be wrong, but 
from reading again, he appears to favor keeping it to .format() syntax?

>> There was probably an edge case or two, but I wasn't expecting

Did anyone discover the strategy below wasn't possible (moving the identifiers)?

     f'{x}{y}'           -->  '{}{}'.format(x, y)

     f'{x:10}{y[name]}'  -->  '{:10}{[name]}'.format(x, y)

> Also, what'syour concern with the suggested approach? There are no security concerns
> as there would be with eval-ing arbitrary strings.

That's true I suppose, and perhaps I'm being irrational but it feels like a 
complex solution, a pandora's box if you will.  To put it another way, it's way 
more power than I was expecting.  It's rare that I use even the advanced 
features of .format() as it is.

I'm guessing that despite the magic happening behind the scenes, people will 
still think of the format string as an (interpolated) string, like the shell. 
If they want to write arbitrary expressions they can already do that in python 
and then format a string with the answers.  This will be another way to write 
code, that's (as far as I know) not strictly necessary.

Also I thought, that the simpler the concept, the greater likelihood of PEP 
acceptance.  Binding the format string to .format() does that, in the mind at 
least, if not the implementation.

Still, if this is what most people want, I'll keep quiet from now on. ;) 
(Thanks for taking this on, btw.)

-Mike