I checked component pascal again. I was wrong - it is cil, too. So it might run on mono. Active Oberon has still some advantages :-) - it is easier, to get it working: op has 4 MB and a lot of files. aob has few line of code. - op needs a runtime-lib - aob is "smarter" however, as things look now, I think we could get op working, too. But it might be more work