Michael Chermside wrote:
> Brett responds:
>> Yeah, I see what you are saying. But I actually held this view long
>> before Iearned how Python did things underneath the covers.
>>
>> I have no clue how people tend to view things. Anyone else care to
>> comment on how they tend to see arguments?
>
> My mental model matches Brett's.
I think of them as separate things, too. Separate attributes also makes it
easier to add additional metadata later, and the structure of each attribute
can be well-defined.
For example, given:
def f(req:int, opt=val, *args, reqkwd, optkwd=val2, **kwds):
pass
A signature object like the following would then be relatively easy to grasp:
sig = f.__signature__
assert sig.required_args == ('req',)
assert sig.optional_args == ('opt',)
assert sig.extra_args == 'args'
assert sig.required_keywords == ('reqkwd',)
assert sig.optional_keywords == ('optkwd',)
assert sig.extra_keywords == 'kwds'
assert sig.defaults == dict(opt=val, optkwd=val2)
assert sig.argtypes == dict(req=int)
Note that this can easily be adjusted for changes in signature expressiveness.
Without keyword only arguments or argument type, the example might look like:
def f(req, opt=val, *args, **kwds):
pass
sig = f.__signature__
assert sig.required_args == ('req',)
assert sig.optional_args == ('opt',)
assert sig.extra_args == 'args'
assert sig.extra_keywords == 'kwds'
assert sig.defaults == dict(opt=val, optkwd=val2)
The simplest example:
def f():
pass
sig = f.__signature__
assert sig.required_args == ()
assert sig.optional_args == ()
assert sig.extra_args == ''
assert sig.extra_keywords == ''
assert sig.defaults == {}
A sequence+enum approach is really hard to adapt to changes in signature
expressiveness, whereas an attribute based approach can just add more tuples
and string-keyed dictionaries for all relevant information.
Cheers,
Nick.
--
Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
---------------------------------------------------------------
http://www.boredomandlaziness.org
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