</tt> or the label plus <tt>right</tt>.  These correspond 
to the left and
right locations in the input stream to which that terminal or
non-terminal came from.  These values are propagated from the input
terminals, so that the starting non-terminal should have a left value of
0 and a right value of the location of the last character read.<p>

For more information, refer to the manual on <a href="#label_part">positions</a>. 

</p><h5><a name="ret_val">Return Value</a></h5>

A call to <tt>parse()</tt> or <tt