Re: [Swig-user] Wrapping of C++ method with one default argument for python

[Willis C. <wc...@pd...>]

Got it working with "compactdefaultargs". Thanks Josh.

-----Original Message-----
From: Josh Cherry [mailto:jc...@nc...] 
Sent: Thursday, February 17, 2011 10:30 AM
To: Willis Cheung
Cc: swi...@li...
Subject: Re: [Swig-user] Wrapping of C++ method with one default argument
for python



On Thu, 17 Feb 2011, Willis Cheung wrote:

> I have had couple methods taking in multiple default arguments which swig
> wrapped into several overloaded methods, which worked fine. However, for a
> C++ method with single default argument like the following:
>
> void Foo(Foo2 f = 0)
>
> it gets wrapped as two overloaded methods as well in the .cxx created by
> swig, one calling Foo() and the other calling Foo(Foo2), which looks fine.
> In the swig generated python source file however, I see the following:
>
> def Reset(self, f = 0): return _Python.Foo(self, f)
>
> This would seem to always generate the dispatch to call the Foo(Foo2)
method
> in C++. As a result, I would get "NotImplementedError: Wrong number or
type
> of arguments for overloaded function 'Foo'" if I try to call Foo() in
> python.

I presume that "Reset" should be "Foo".

I imagine the problem has nothing to do with the number of (default) 
arguments.  Rather, it has to do with the fact that the C++ default 
depends on an implicit conversion of 0 to a Foo2, which doesn't carry over 
to Python (unless you do something to enable it).  You may be able to get 
around this by using the "compactdefaultargs" feature:

http://www.swig.org/Doc2.0/SWIGPlus.html#SWIGPlus_default_args

Josh