duck typing assert

Prasad, Ramit ramit.prasad at jpmorgan.com
Fri Nov 9 18:37:29 CET 2012


Andriy Kornatskyy wrote:
> 
> Thank you for all comments.
> 
> > It makes very good sense to say:
> >
> > duckmatch(IFoo).compare(Foo)
> 
> Since we do duck match of IFoo... but there is no `duck match`, there is `duck test`. I believe instead of
> `compare` is more readable with `equals`. Than it is more from mathematics - precise answer... that you can not
> guarantee at all in dynamic programming language. So it false to use such wording to reflect this check. We can
> only make an assumption that one looks like the other (similar)... with some limitation of cause...
> understanding what is `duck test`.
> 
> http://en.wikipedia.org/wiki/Duck_test
> 
> The intent is to make such language `construct` so it reads as English sentence that make sense, and not
> mandatory `pythonic` way (readability counts, java smokes aside).
> 
> is_similar(Foo).to(IFoo) # <= but we lost `duck test` sense here?
> 
> Words `looks` and `like` are coming from duck test and point also direction:
> 
> # 1
> looks(Foo).like(IFoo, notice=['__len__'], ignore_funcs=['foo'], ignore_argspec['bar'])
> 
> English sentence equivalent: if functions in Foo looks like one in IFoo than, probably, IFoo can be replaced
> with Foo; notice to check __len__, it is safe to ignore function `foo` and arguments passed to `bar`.
> 
> # 2
> looks(Foo, notice=['__len__'], ignore_funcs=['foo'], ignore_argspec['bar']).like(IFoo)
> 
> English sentence equivalent: while looking at Foo notice to check `__len__`, it is safe to ignore function `foo`
> and arguments passed to `bar`, than probably it like IFoo.

What about?

duck(Foo).equivalent_to(IFoo, <kwargs>) 
duck(Foo).matches(IFoo, <kwargs>)

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