[PPL-devel] client data for ppl_io_set_variable_output_function?

Hello Roberto and all,

It would be cute if the routine passed to ppl_io_set_variable_output_function could take some client data.

So I suggest an additional variant to the API. In C++, have inside the Parma_Polyhedra_Library::Variable class typedef void output_function_with_data_type (std::ostream &s, const Variable &v, void* data); and the static member function set_output_function_with_data(output_function_with_data_type* f, void *data); so that when a variable v needs to be output, PPL would call f(s,v,data)

And in the C API one would have

ppl_io_set_variable_output_with_data_function(ppl_io_variable_output_function_with_data_type *f, void*data)

Regards.