ng
          of sequences the same way as the std::stream libraries do: we use operator
          <code class="computeroutput"><span class="char">'&gt;&gt;'</span></code> for input (parsing),
          and operator <code class="computeroutput"><span class="char">'&lt;&lt;'</span></code> for output
          (generating). Other than that there is no significant difference. The above
          program creates a generator from two simpler generators, glueing them together
          with the sequence operator. 