al">[</span><span class="identifier">str</span><span class="special">.</span><span class="identifier">size</span><span class="special">()];</span>
    <span class="keyword">bool</span> <span class="identifier">r</span> <span class="special">=</span> <span class="identifier">lex</span><span class="special">::</span><span class="identifier">tokenize</span><span class="special">(</span><span class="identifier">first</span><span class="special">,</span> <span class="identifier">last</span><span class="special">