ref="index.html#type-t">t</a></code></dt><dt class="spec value" id="val-add"><a href="#val-add" class="anchor"></a><code><span class="keyword">val</span> add : <a href="../Source/index.html#type-t">Source.t</a> <span>&#45;&gt;</span> <a href="index.html#type-t">t</a> <span>&#45;&gt;</span> <a href="index.html#type-t">t</a></code></dt><dt class="spec value" id="val-get_footprint_indexes"><a href="#val-get_footprint_indexes" class="anchor"></a><code><span class="keyword">val</span> get_footprint_indexes : <a 