Well done Edgar - I have wanted to do this for a while but had no time. I do find Xtext to be a little buggy and heavyweight, but it does the job. I wish they would move to ANTLR v4 and had not decided to change the standard syntax (it makes sharing grammars between compilers and xtext projects a bit of a PITA). But all in all it does what it says on the box and these things are quite complex to maintain (and Eclipse doesn't help ;).
Thanks for the effort - I will be using it heavily so I will give you constructive feedback when I can :).
Perhaps you should/could add StringTemplate 4 support to the project - given that you probably have a lot of the guts of what would be needed, you might find it fairly easy; just adding coloration would help a lot of people I think.
Cheers,
Jim