ss="keyword">type</span> <span>'a t</span></code><code> = <a href="argument-1-T/index.html#type-t">T.t</a> <span>&#45;&gt;</span> <span class="type-var">'a</span></code></dt></dl><dl><dt class="spec value" id="val-map"><a href="#val-map" class="anchor"></a><code><span class="keyword">val</span> map : <span>(<span class="type-var">'a</span> <span>&#45;&gt;</span> <span class="type-var">'b</span>)</span> <span>&#45;&gt;</span> <span><span class="type-var">'a</span> <a href="index.html#type-t">t</a></span> <sp