SESS constant a not that good idea?

First of all i am not that familiar with the constants behaviour of PHP: will a define("SESS","sometext") and later <?php SESS?> not produce a syntax error as sometext is not supposed to be valid PHP source? dont we need a clever way to generally do a <a href="<?php surl("FUNURL")"> in all scripts and surl will do the right thing, i.e: - append "?SESSID=sess_id" if no "?" was in FUNURL - append "&SESSID=sess_id" if a "?" was in FUNURL - do not append anything if "SESSID=sess_id" was already part of FUNURL (due to FUNURL being derived from $PHP_SELF or the like) - do not append anything if the session id propagation method was determined to be via cookie earlier in the script / or by PHP ini/config method? For this kind of cleverness a simple constant will not suffice. We have something like surl() in PHPLIB because we want to be able to write scripts independent from the session id propagation method. Moreover: a clever propagation method detection mechanism will do the rest for us. We dont care for the propagation method. That mechanism resides in a prepend file and the surl() like function decides if there has to be done modification to the given url. Just some thoughts... Boris