Tim Hochberg wrote:
> Ian Bicking wrote:
>> Alex Martelli wrote:
>>> As for the % operator, I never liked it -- either a builtin
>>> function, or even better a method of string objects, is going to be
>>> much more readable (and my preference would be to have it take
>>> optional positional arguments, corresponding to {1}, {2}, etc, and
>>> optional named arguments, corresponding to {name} &c).
>>
>>
>>
>> Note that if it takes keyword arguments, but doesn't take a single
>> dictionary-like object (like % and string.Template.substitute do),
>> then you lose any ability to use clever or interesting dictionary-like
>> objects for substitution.
>>
>
> Why doesn't the ** take care of this? To take your example, why doesn't
> this work?
>
> string.Template(pattern).substitute(**EscapingWrapper(**EvalingWrapper(**locals()))
>
>
>
> Is it that you feel that adding ** is too much of a syntactic burden, or
> am I just missing something?
func(**kw) actually passes a dictionary to func. EvalingWrapper isn't a
dictionary, it's just an object with a __getitem__. ** can't be changed
in this way, either -- it really has to enumerate all the keys in the
thing passed to it, and there's no way to enumerate all the keys in a
wrapper like EvalingWrapper.
Any string substitution only needs __getitem__, so these constraints
when calling a function with ** do not apply to the actual string
substition.
--
Ian Bicking / [EMAIL PROTECTED] / http://blog.ianbicking.org
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