>> Is there an easy (i.e.: no regex) way to do get the names of all
>> parameters?
>>
>> get_parameters(template) should return ["name", "action"]
>
> How about:
>
> class gpHelper:
> def __init__(self):
> self.names = set()
> def __getitem__(self, name):
> self.names.add(name)
> return 0
>
> def get_parameters(template):
> hlp = gpHelper()
> template % hlp
> return hlp.names
>
>>>> template=""" Hello %(name)s, how are you %(action)s"""
>>>> get_parameters(template)
> set(['action', 'name'])
(darn, if I didn't have nearly identical code/reply, but two
posts beat me to the Send button)
Duncan's solution is a slightly more robust solution (returning 0
rather than returning the empty string), as format strings allow
for things like
"%(food)s costs $%(x)05.2f" % {
'x':3.14159,
'food':'a slice of pie'
}
which will choke if it gets a string instead of a number for
attempts to get "x".
It sure beats trying to hammer out a regexp or some stab at
pyparsing it. Though I suppose one could do something like
r = re.compile(r'%\(([^)]*)\)')
as most of the edge-cases that I can think of that would cause
problems in a general case would be problems for the string
formatting as well (balanced parens, etc)
-tkc
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