It uses IOlib based clws library for the communication between the Mozilla XULRunner and Common Lisp via web sockets. Because of the IOlib limitation, it works only on Linux at the moment, until a platform independent implementation of websockets is found. Also, I've only tried it from SBCL so far.
CL-XUL implements a component-based architecture, standard widgets support, easy communication between client and server and automatic view updates and a readable description of GUI directly in Common Lisp, with no need of external XML files.
This is still work in progress, and there's no documentation at the moment (it is coming soon, though) but a demo can be tried.
As of December 26 of 2013, CL-XUL can be obtained from Quicklisp.
(ql:quickload :cl-xul) to download and install the system, and
(ql:quickload :cl-xul-test) followed by
(xul-test:showcase) to run the demo.
Alternatively, download the source code from here and point
cl-xul-test.asd system definition files from
./sbcl/system (ln -s <system definition file path>) and then evaluate:
from your lisp listener.
You will also need to satisfy the system dependencies:
The easiest way of installing those packages is via Quicklisp.
This library is under the MIT licence.