less.js is much slower in Nashorn than in Rhino.

http://houbie.blogspot.ca/2013/06/javascript-on-jvm-experimenting-with.html

http://mail.openjdk.java.net/pipermail/nashorn-dev/2013-June/001448.html

I'm attaching a modified version of less-1.3.3.js that runs with nashorn (run with -scripting to enable readFully())