an 
class="pcrb7t-">&#x00A0;Ptr</span><span 
class="pcrb7t-">&#x00A0;a</span><span 
class="pcrb7t-">&#x00A0;-&#x003E;</span><span 
class="pcrb7t-">&#x00A0;IO</span><span 
class="pcrb7t-">&#x00A0;(Maybe</span><span 
class="pcrb7t-">&#x00A0;b) </span></td>
</tr></table>                                                                                   </div> <dd class="haddockdesc">
     Convert a peek combinator into a one returning <span 
class="pcrr7t-">Nothing</span><a 
 id="dx42-303007"></a> if applied to