[Python-ideas] Draft PEP on string interpolation

[Ron Adam]

On 08/27/2015 04:17 AM, Eric V. Smith wrote:
>>> n = 10
>>> >>s = 'text'
>>> >>x = i'{n}:{s}'
>>> >>
>>> >>to_list(x)  -> [10, ':', 'text']
>>> >>to_repr(x)  -> '10:"text"'
>>> >>
>>> >>And this doesn't even take into account the format_specs or conversions,
>>> >>which only have meaning to the conversion function.
>> >
>> >Sure it does, you can access the format spec and apply it manually to
>> >each item or not.  Is there another choice?
> You're not reading what I'm writing. Using your proposal of immediately
> converting to strings, how would you write the version of "to_list"
> whose output I show above?
>
>> >Depending on how you want to make the values and specs visible.
>> >
>> >    def to_repr(istr):
>> >        return ''.join(repr(item.format(spec)) for item, spec
>> >                   in istr.items())


Well, what you have above is applying repr to the values but not the 
literal parts.  It's doable, but that should really be part of the 
format spec rather than applying a function from outside, or it should 
be part of the expression in the i-strings.

          i'{repr(n)}:{repr(s}}'
          i'{n!r}:{s!r}'

Yes, this topic is getting too drawn out.  Possibly I'm not seeing a 
finer point in your examples.  I think it will sort it self out as the 
implementation progress's, so I'm not too worried about it.

I'll look at the code in your repository when I have time and try to 
keep things to concrete examples that you can use in your tests if I 
have time.

Cheers,
    Ron