title: how to implement mapAccumRM?
body: <p>I asked a similar question before (<a href="https://stackoverflow.com/questions/11652809/how-to-implement-mapaccumm">how to implement mapAccumM?</a>).</p>
  
  <p>I need the one which folds from the right as well (<code>mapAccumR</code>):</p>
  
  <pre><code>mapAccumRM :: (Monad m, Traversable t) 
             =&gt; (a -&gt; b -&gt; m (a, c)) -&gt; a -&gt; t b -&gt; m (a, t c)
  </code></pre>
  
  <p>Is there a simple implementation for this?</p>