type-var">'acc</span> <span class="arrow">&#45;&gt;</span></span> <span>string <span class="arrow">&#45;&gt;</span></span> <span class="type-var">'acc</span>)</span> <span class="arrow">&#45;&gt;</span></span>
  <span><span class="label">init</span>:<span class="type-var">'acc</span> <span class="arrow">&#45;&gt;</span></span>
  <span class="type-var">'acc</span></span></code></div><div class="spec-doc"><p>Takes a process handle where both stdin and stdout are set to pipe and folds over output. See <a href=