[Python-3000] String formating operations in python 3k

[Eric V. Smith]

> If I were designing a formatting system from scratch,
> I think I'd separate the issue of formatting numbers into
> strings from the issue of inserting strings into other
> strings. So instead of
> 
>    "Answer no. %5d is %8.3f" % (n, x)
> 
> you would say something like
> 
>    subst("Answer no. {1} is {2}", format(i, 'd', 5), format(x, 'f', 8, 3))

Doesn't this violate Guido's "don't have a parameter that is always a 
constant that changes how a function operates" principle (or whatever 
its formal name is)?  In this case, that's the type identifier 'd' or 
'f'.  I think format_int(i, 5) and format_float(x, 8, 3) would be 
better.  Or maybe a format() member of int and float, which take 
different parameters.  It's unlikely you'd need to specify the type 
identifier at runtime.

But I agree with separating string insertion from number formatting. 
You'd probably need to support locales with the number formatting.

Eric.