r_p</tt> will 
  eat up all the input up to the end of the input stream). So we have to refactor 
  this into:</p>
<pre><span class=special>       </span><span class=special>*(</span><span class=identifier>anychar_p </span><span class=special>- </span><span class=identifier>ch_p</span><span class=special>(</span><span class=literal>','</span><span class=special>))
    </span><span class=special>&gt;&gt; </span><span class=special>*( </span><span class=identifier>ch_p</span><span class=special>(</span><span 