Parsers vs. processors

just a question about input of XSL processor, 

XML doc --> xml parser --> xml doc --> xsl proc -->
..
XML doc --> xsl proc -->..

does this two cases work ?
are we oblige first to use an XML parser before using
XSL processor?


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list