[Python-Dev] Multiple dicts for string interpolation?

[Skip Montanaro]

    Tim> Skip, is the long-windedness of

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

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

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

    Tim> instead so you could use it as a one-liner

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

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

The long-windedness was part of it.  The performance hit of composing
dictionaries thousands of times to perform a single format operation was
also a consideration.

Okay, side excursion into the Zope source tree...

What I was calling MultiDict is actually MultiMapping (written in C, BTW).
As a side effect of my Zope install here, I even already have it in sys.path
(go figure!).  And it turns out to work just as Tim surmised:

    >>> d1 = {"a": 1}
    >>> d2 = {"b": 2}
    >>> d = MultiMapping.MultiMapping(d1, d2)
    >>> d["b"]
    2
    >>> d["a"]
    1

Dang!  Turns out Jim Fulton has a time machine also.

I guess the next question is to extend Ken's comment about getting it into
the Python core.  Would that be something possible for 1.6?  I used a Python
version of MultiMapping in an ancient version of DocumentTemplate.  I'm sure
the C version has been around for at least two or three years and would
appear pretty darn stable, since it seems to be at the core of a lot of
Zope's coolness.

Skip