class="lineno">  101</span>&#160;    <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">bool</span> is_mutable = <span class="keyword">false</span>;</div><div class="line"><a name="l00102"></a><span class="lineno">  102</span>&#160;    P operator()(P)<span class="keyword"> const </span>{ <span class="keywordflow">throw</span>; }</div><div class="line"><a name="l00103"></a><span class="lineno">  103</span>&#160;};</div><div class="line"><a name="l00104"></a><span