">t</a> <span class="arrow">&#45;&gt;</span></span> <span class="type-var">'a</span></span></code></div><div class="spec-doc"><p>Same function as <code>List.fold_left</code> but on segments of a given polygon</p></div></div><div class="odoc-spec"><div class="spec value" id="val-fold_filter" class="anchored"><a href="#val-fold_filter" class="anchor"></a><code><span><span class="keyword">val</span> fold_filter : 
  <span><span>( <span><a href="../Point/index.html#type-t">Point.t</a> <span class="arrow">&#45;&