There has been a few requests from people to have the ability to turn x10 devices on and off from hal. I currently don't have any x10 devices, although I am considering some for my observatory, I noticed a way to make it work if you are using the homeseer program (
www.homeseer.com) It's not a free utility ($159) but I understand it is very popular among x10 users. What caught my eye was the free command line utility download to use with homeseer. This gives you the ability to run the command line utility, and pass variables to homeseer to control x10 devices.
I realized that by modifying the mywebhal.uhp file, I can setup a line that would look for keyword lets say "turn on light a40" then instead of a url run command, you can insert the command line utility with the required variables. When the match is made, hal will execute the run time utility with the code to execute the desired effect, in this case turn on a light. I've done some basic testing and I am able to run executables from the mywebhal.uhp.
This will require manually editing the mywebhal.uhp for each x10 device, but it appears it will work and give you control of x10 devices from hal.
Glenn