 class="identifier">U</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <a name="boost.proto.shift_left_assign.proto_grammar"></a><span class="identifier">proto_grammar</span><span class="special">;</span>

  <span class="comment">// member classes/structs/unions</span>
  <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <a class="link" href="../../Expr.html" title="Concept Expr">Expr</a><span class="special">,</span> <span c