" class="anchor"></a><code><span><span class="keyword">val</span> take_while : <span>?sep_by:<span><span class="type-var">_</span> <a href="#type-t">t</a></span> <span class="arrow">&#45;&gt;</span></span> <span>while_:<span>bool <a href="#type-t">t</a></span> <span class="arrow">&#45;&gt;</span></span> <span><span><span class="type-var">'a</span> <a href="#type-t">t</a></span> <span class="arrow">&#45;&gt;</span></span> <span><span><span class="type-var">'a</span> list</span> <a href="#type-t">t</a></span>