d_mapi : <span><a href="#type-t">t</a> <span class="arrow">&#45;&gt;</span></span> <span><span class="label">init</span>:<span class="type-var">'a</span> <span class="arrow">&#45;&gt;</span></span> <span><span class="label">f</span>:<span>(<span><a href="../index.html#type-t">t</a> <span class="arrow">&#45;&gt;</span></span> <span><span class="type-var">'a</span> <span class="arrow">&#45;&gt;</span></span> <span><a href="#type-value">value</a> <span class="arrow">&#45;&gt;</span></span> <span class="type-va