[C++-sig] init from free function instead of constructor

[John Reid]

One more related question. :)

So now I want to use implicitly_convertible but I can't get this to do 
what I want.

Is there any way of doing something equivalent to:
	implicitly_convertible< std::string, X >();
in the example below?

There is no constructor for X that takes a std::string, but when 
boost.python is matching arguments at run-time couldn't it realise that 
it knows how to make a wrapped X from a std::string and therefore can 
convert a string to an X? If so I would like to make this feature request.

Thanks,
John.



John Reid wrote:
> OK this seems to work, I haven't got my head around why return by value 
> wouldn't:
> 
> struct X {
> 	typedef boost::shared_ptr< X > ptr;
> 	std::string _s;
> 	X( const std::string & s = "test" ) : _s( s ) { }
> };
> X::ptr make_x( ) { return X::ptr( new X ); }
> X::ptr make_x_from_string( const std::string & s ) { return X::ptr( new 
> X( s ) ); }
> void export_x()
> {
> 	using namespace boost::python;
> 	class_< X > x( "X", no_init );
> 	x.def( "__init__", make_constructor( make_x ) );
> 	x.def( "__init__", make_constructor( make_x_from_string ) );
> 	x.def_readonly( "string", &X::_s );
> 	register_ptr_to_python< X::ptr >();
> }
> 
> Thx,
> John.