I spend a lot of my time these days working on ASL scripts to enhance Smarts solutions. Most of that time is spent on Linux, working with "VIM" as the editor of choice. It was therefore a natural step for me to try to configure VIM's syntax colouring logic to give colour to ASL.
After a little research, I found it was surprisingly easy to do. In case you may find it helpful - here's my attempt at the challenge. It's not perfect yet, and I hope it'll improve over time. It would be helpful if you let me know of any issues you have with it.
Here's an example of how the result looks in a "putty" session..
Download and Installation
First: put the following line in your ".vimrc" file..
au BufNewFile,BufRead *.asl setf asl
Then: download this file, copy it into your ".vim/syntax" folder and give it the name "asl.vim".
Now - edit a few .asl files with vim and enjoy.