(Wikipedia): The Postscript language is a vectorial drawing format used to describe a page. It is an interpreted, stack-based language. The language syntax uses reverse Polish notation, which makes the order of operations unambiguous, but reading a program requires some practice, because one has to keep the layout of the stack in mind.
For example, the following postscript program draws a line from the point (0,0) to (100,100):
0 0 moveto
100 100 lineto
I've played with postscript and created a XSLT stylesheet transforming a simple SVG document to postscript. The stylesheet is available here: svg2ps.xsl.
The following SVG document
was transformed using my XSLT stylesheet, and here the result uploaded into scribd.com:
A Simple SVG document transformed to PDF with XSLT