# File lib/buildr/ide/eclipse.rb, line 46
      def classpath_variables(*values)
        fail "eclipse.classpath_variables expects a single hash argument" if values.size > 1
        if values.size == 1
          fail "eclipse.classpath_variables expects a Hash argument" unless values[0].is_a? Hash
          # convert keys to strings
          values = values[0].inject({}) { |h, (k,v)| h[k.to_s] = @project.path_to(v); h }
          @variables = values.merge(@variables || {})
        end
        @variables || (@project.parent ? @project.parent.eclipse.classpath_variables : default_classpath_variables)
      end