On 07/20/2015 01:25 PM, Guido van Rossum wrote:
Perhaps surprisingly, I find myself leaning in favor of the f'...{var}...' form. It is explicit in the variable name.
Historically, the `x` notation as an alias for repr(x) was meant to play this role -- you'd write '...' + `var` + '...', but it wasn't brief enough, and the `` are hard to see. f'...' is more explicit, and can be combined with r'...' and b'...' (or both) as needed.
We didn't implement b''.format(), for a variety of reasons. Mostly to do with user-defined types returning unicode from __format__, if I recall correctly. So the idea is that f'x:{a.x} y:{y}' would translate to bytecode that does: 'x:{a.x} y:{y}'.format(a=a, y=y) Correct? I think I could leverage _string.formatter_parser() to do this, although it's been a while since I wrote that. And I'm not sure what's available at compile time. But I can look into it. I guess the other option is to have it generate: 'x:{a.x} y:{y}'.format_map(collections.ChainMap(globals(), locals(), __builtins__)) That way, I wouldn't have to parse the string to pick out what variables are referenced in it, then have .format() parse it again. Eric.