Re: [Swig-devel] C++ "properties" to members in SWIG

[David P. <dpi...@me...>]

> I'm tinkering with a patch to Swig_wrapped_member_var_type().
Basically,
> the patch is that if we're using C++, and the member variable is due
to
> %extend, and is a %naturalvar, use a value type instead of a const
> reference type.

Hmm, I notice there is no problem when SWIG is wrapping a function that
returns a string. Do you happen to know why that is?

I'm not sure your proposal would be acceptable in all cases. Consider
cases like this (basically, the following is what %attribute_ref is
for):

%ignore Foo::X()
%extend Foo {
  string x;
}
#define Foo_x_get(obj) obj->X()
#define Foo_x_set(obj, value) obj->X() =3D value

class Foo {=20
  string _x;
  public: int& X() { return _x; }
}

Although "x" is added by %extend, it actually does refer to a variable
inside the class (_x).
=20
> It may be more interesting to have a variation on %naturalvar that
> states a preference to use values instead of references.

To generalize the solution, I suspect there should be a typemap to
control $1_ltype (as explained in the manual section 26.7.3: "All
arguments and local variables in wrapper functions are declared using
this type so that their values can be properly assigned.")