Listing 6: The class ArgumentList

#ifndef ARGLIST_H
#define ARGLIST_H

#include<vector>

#include"variant.h"

class ArgumentList
{
  public:

    // Ctor, Dtor, CopyCtor, and Assign ommited
    // because the defaults are apropriate.

    template<typename T> void push_back ( T Value )
      { _container.push_back ( variant_t ( Value ) ) ; }

    // NOTE: This returns a COPY of the value at pos idx.
    template<typename T> T operator [] ( size_t idx ) const
      { return _container [ idx ] ; }

    // This form returns a REFERENCE and not a COPY.
    template<typename T> const T & at ( size_t idx ) const
      { return _container [ idx ].get<T>() ; }

    bool   empty() const { return _container.empty(); }
    size_t size () const { return _container.size (); }

  private:
    std::vector<variant_t> _container ;
} ;

#endif