[C++-sig] void* cast to a specific type based on string name

[David Abrahams]

on Mon Oct 06 2008, "Renato Araujo" <renatox-AT-gmail.com> wrote:

> Hi,
>
> for this case I would like  to know if is possible create a python
> object based on string name like that:
>
>
> void call_Pyfunction(int argc, char **types, void **args,
> boost::python::object *callbak)
> {
>    boost::python::list pyArgs;
>    for (int i=0; i <= count; i++)
>    {
>          //in types I have the typenames: {"int", "string", "MyObject", ....}
>          boost::python::object o(types[i], args[i]);
>         pyArgs.append(o);
>     }
>     callback(pyArgs);
> }

Sure, just build a map from type names to conversion functions:

      std::map<std::string, python::object(*)(void*)> m;

      template <class T>
      python::object void_ptr_to_python(void* p)
      {
          return python::object(*(T*)p);
      }

      m["int"] = &void_ptr_to_python<int>;
      m["string"] = &void_ptr_to_python<std::string>;
      m["MyObject"] = &void_ptr_to_python<MyObject>;

Then,

       m[types[i]](args[i])

will do the trick.

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com