title: What happens when you have a conditional operator and a postfix conditional in the same Perl statement?
body: <p>Can anybody explain how this line works?</p>
  
  <pre><code>return $y &lt; 0 ? - pip2 : pip2 if $x == 0;
  </code></pre>
  
  <p>if <code>$y &lt;0</code> it returns <code>-pip2</code>, but what it returns when <code>$y &gt;= 0</code> and <code>$x != 0</code> ?</p>
  
  <p>This line is from this function:</p>
  
  <pre><code>sub _atan {
      my( $y, $x ) = @_;
  
      return $y &lt; 0 ? - pip2 : pip2 if $x == 0;
      return atan( $y / $x );
  }
  </code></pre>