Guido van Rossum <guido@python.org> writes:
How about:
extract(attr='grade') extract(item=2) extract(method='foo') # returns the result of calling 'ob.foo()'
And following the pattern of Zope's old "query" package:
extract(extract(attr='foo'), attr='bar') # extracts ob.foo.bar extract(extract(item=10), method='spam') # extracts ob[10].spam()
i.e., the first (optional) positional argument to extract is a function that's called on the outer extract's argument, and the return value is then used to perform the main extract operation on.
I'm not sure what the advantage of this is. It seems more typing, more explanation, probably more code to implement (to check for contradicting keyword args).
Hm, couldn't "lambda ob: ob.foo.bar" return exactly the same thing as "extract(extract(attr='foo'), attr='bar')" ? In other words: return specialized C implemented functions for simple lambda expressions? Thomas