[Python-Dev] Multiple dicts for string interpolation?

[Tim Peters]

[Skip, wants to interpolate multiple dicts via "%",
 suggests passing a tuple of dicts:  format % (d1, d2, ...)]

[Guido]
> ...
> I think it depends on to what extent this is a common, useful
> idiom.  Do you have evidence of that?  Examples?

You yourself raised one last century <wink>:  simply wanting to interpolate
from both locals() and globals().  At the time, the idea of a new dict-like
mapping object (capturing Python's lookup rules) appealed to you.  I still
like that, and note that the apparent need becomes more acute if "deep
nesting" is ever added.

I wasn't aware of the MultiDict approach Skip mentioned, but thought it
looked spot on for the general case!  Skip, is the long-windedness of

    dict = MultiDict()
    dict.append(d1)
    dict.append(d2)
    ...
    s = format % dict

the part you didn't like about that?  If so, how about changing the
constructor to

    def __init__(self, *dicts):
         ...

instead so you could use it as a one-liner

    format % MultiDict(d1, d2, ...)

?  That's exactly the same as the tuple idea, except there's a nice
descriptive word in the middle of it <wink>.