Method assign

ext/include/boost/optional/optional.hpp:266–279

Assigns from another optional (deep-copies the rhs value)

    // Assigns from another optional<T> (deep-copies the rhs value)
    void assign ( optional_base const& rhs )
    {
      if (is_initialized())
      {
        if ( rhs.is_initialized() )
             assign_value(rhs.get_impl());
        else destroy();
      }
      else
      {
        if ( rhs.is_initialized() )
          construct(rhs.get_impl());
      }
    }

#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
    // Assigns from another optional<T> (deep-moves the rhs value)