I tried to get the cperl-mode.el provided in pugs/util a few times before, but I always got an error message telling me something like
And basically, I could never get any further and edit Perl 6 code with a proper Emacs mode. Today, I tried again, but instead of giving up, I tried to locate the problem. I started with emacs -q which does not load my .emacs file, so my Emacs was all fresh. I quickly added the correct load-path for the newer cperl-mode.el and when I opened foo.pl, no problem. So the problem was lying somewhere in my .emacs.
The first section of my .emacs are the load-path additions. One by one, I commented them out, restarted Emacs and tried to find where the problem was. When I removed ~/elisp/ruby/ from my load-path, cperl-mode.el worked perfectly. Adding it again, cperl-mode.el failed to load.
So, somehow there is a problem between these two modes. I don’t know how this happened, but I downloaded ruby-1.9 to get the latest .el files, and it didn’t fix the problem. I pinpointed the problem to inf-ruby.el. So now, everything related to inf-ruby is commented in my .emacs file until the problem can be resolved.