azy_argument">Lazy
            Argument</a> is typically a test that is called to resolve ambiguity
            in the grammar. A parse failure will be reported when the <a class="link" href="../basics.html#spirit.qi.reference.basics.lazy_argument">Lazy
            Argument</a> result evaluates to <code class="computeroutput"><span class="keyword">false</span></code>.
            Otherwise an empty match will be reported. The general form is:
          </p>
<pre class="programlisting"><span class="identifie