-operator">)</span><span class="mdzsyn-operator">;</span>
    <span class="mdzsyn-keyword">if</span> <span class="mdzsyn-operator">(</span><span class="mdzsyn-identifier">index</span> <span class="mdzsyn-operator">&lt;</span> <span class="mdzsyn-identifier">0</span><span class="mdzsyn-operator">)</span> <span class="mdzsyn-operator">{</span>
        <span class="mdzsyn-identifier">janet_panicf</span><span class="mdzsyn-operator">(</span><span class="mdzsyn-string">"expected non-negative 64 bit integer, got 