From: Brian Lloyd <brian@digicool.com>
BASEPATHx (and its converse URLPATHx) are analogous to the current BASEx and URLx variables of the REQUEST object, except that they take any fiddling of the path (such as that done by SiteAccess) into account. They will be introduced in the next feature release (2.3). BASEx and URLx will continue to work, but will be deprecated in favor of the new BASEPATHx and URLPATHx.
Whoa there! BASEPATHx and URLPATHx are the path portion of BASEx and URLx respectively. That is, if BASE1 == "http://www.foo.com/x/y/z" then BASEPATH1 == "/x/y/z". All of these take path manipulation into account. It's SCRIPT_NAME, REQUEST.script, and the various surgical contortions which try to extract the path part of URLs that are deprecated by these newcomers. Any place SCRIPT_NAME used to appear, it should be replaced with BASEPATH1. Cheers, Evan @ digicool & 4-am