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Keyword arguments and user-defined dictionaries

G. S. Hayes sjdevnull at yahoo.com
Thu Jun 24 14:38:44 EDT 2004 
Christopher T King <squirrel at WPI.EDU> wrote in message news:<Pine.LNX.4.44.0406241012001.8058-100000 at ccc8.wpi.edu>...
> > My question is, what methods do I need to implement to make ** work on
> > a custom dictionary-like object, or is it not possible?
> 
> As far as I can tell, it's not possible.....
[SNIP]
> > If the syntax "**expression" appears in the function call, "expression" 
> > must evaluate to a (subclass of) dictionary
> 
> which seems pretty indicative that Python's shortcutting function calls
> for efficiency reasons.

Darn. 

> Your best bet is probably to call the function as func(**dict(mydict)). 
> dict() doesn't shortcut custom methods, so this should act as expected.

Yeah, I have a .explode() method that tells the dictionary to
de-Lazify everything; that's basically what (**dict)(mydict) would do,
except passing as dict(mydict) would de-Lazify every function call and
.explode() just once (though .explode would keep the exploded values
in memory and dict(mydict) would toss them after the function
returned).

Thanks for your time.
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