Re: [pygccxml-development] binding of a default argument calling a function

[Benoit L. <ben...@mo...>]

Roman Yakovenko wrote:
> On Mon, Jun 28, 2010 at 1:22 PM, Benoit Leveau
> <ben...@mo...> wrote:
>> Hello,
>>
>> In a class, I have the following method:
>> void addLayer( boost::shared_ptr<Color> color = Color::create(1,1,1) );
>>
>> This method is exposed by py++ with the following incorrect code:
>> ClassWrapper_exposer.def(
>> "addLayer",
>> addLayer_function_type( &::MyClass::addLayer ),
>> bp::arg("color")=Color::create(float, float, float)(1.0e+0f, 1.0e+0f) );
>>                              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> note the (float..) part which is incorrect, and only 2 parameters are
>> supplied then
>>
>> Rright now i have to edit the code generated by py++...or maybe I can try to
>> use the following code:
>>
>> boost::shared_ptr<Color> defaultColor() { return Color::create(1,1,1); }
>> void addLayer( boost::shared_ptr<Color> color = defaultColor() );
>>
>> Is it a known bug in py++?
> 
> Yes. basically this is a limitation of the technology, py++ is built
> on - gccxml : http://language-binding.net/pygccxml/upgrade_issues.html?highlight=default#free-and-member-function-default-arguments
> GCCXML is not able to dump any/arbitrary C++ expression. You can find
> a lot of post on this subject in GCCXML mailing list. pygccxml/py++
> tries pretty hard to fix this behavior, but there are cases where it
> fails.
Thanks!
I don't know why I didn't find this page :(
and I didn't think about searching specifically in the gccxml mailing list...
 
> The work-around is pretty simple:
> 
> #f is "calldef_t" instance
> for arg in f.arguments:
>     arg.default_value = "<<<new default value or None>>>"
> 
> thus you will not have to touch generated code.
> 

Works great thanks.
Benoit