 class="hljs-keyword">echo</span> line, <span class="hljs-string">&quot; -&gt; &quot;</span>, parse(line)
  <span class="hljs-keyword">echo</span> parse(line).lefts</code></pre>
<pre><samp>[1,2] -&gt; [1,2]
@[@[true], @[false]]
[[1,2],3] -&gt; [[1,2],3]
@[@[true, true], @[true, false], @[false]]
[9,[8,7]] -&gt; [9[8,7]]
@[@[true], @[false, true], @[false, false]]
[[1,9],[8,5]] -&gt; [[1,9],[8,5]]
@[@[true, true], @[true, false], @[false, true], @[false, false]]
[[[[1,2],[3,4]],[[5,6],[7,8]]],9] -&gt; [[[[1,