[C++-sig] Pyste,Py++: equivalent of swig typemaps?

[Stefan Seefeld]

Mihail Konstantinov wrote:
> Thank you Stefan,
> the typemaps are required, when C++ functions are wrapped that expect arguments which have no direct corresponding type in python, or when standard types have to be interpreted differently.
>
> For example a function void parse_args(int argc, char **argv), which I want to call in python as mymodule.parse_args(["arg1","arg2","arg3"]). The wrapper would have to 
> - count the number of python list items and pass this as argc to the C++ function
> - allocate and fill a list of char* with the strings from the python list.
>   

What about this ?

void parse_args(list argv)
{
  std::vector<std::string> args;
  for (unsigned int i = 0; i != len(argv); ++i)
  {
    extract<char const *> ex(argv[i]);
    if (ex.check()) // If this is really a string...
      args.push_back(ex); // ...copy it into a vector
    else
      throw some_error();
  }
  my_function(args);
}


This does what you seem to want: translates a python list of strings 
into a std::vector<std::string>, and passes it down to a function.
Obviously, you can (attempt to) extract data of arbitrary types from the 
python list, as long as converters exist.

HTH,
       Stefan

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