The source is distributed under the terms of the GNU General Public License. It is no longer maintained by the author.
The source as distributed should compile on Unix systems. If you want to compile it on anything else then you should modify mappings.h.
To compile on Unix systems, unpack the source files into a directory of your choice and type the following from that directory:
g++ -fno-for-scope -fno-operator-names -D__unix__ *.cpp -o clara
Then type: ./clara
The program should then prompt you for a random number seed and the number of bars to write in each phrase, and then begin displaying things to indicate that it's doing something. (Don't try to log all this as the log can get very big.) When finished, it should leave the piece in a file with the extension .MWR, which is an input file to Manuscript Writer.
If you're adventurous, you can try some parallel processing by running another instance of the program in the same directory - it should begin helping out. Of course, you need multiple processors to do this (or multiple machines using NFS). The program was originally designed to run as a background task on about 20 DOS machines, and it is resilient to individual machines crashing or whatever (you can actually get it to save its state, but at today's speeds there is little point).
Source code (gzipped tar archive, 51K)