Laurent is working on an Interpreter View for Acceleo 3.2 (coming soon)
It feels good already, one can launch queries on any Editor or View, syntax higlighting works and so is completion proposals. Compilation errors are shown too.
It's the perfect companion for building your code generator, once you'll start using it you will wonder how you could live without it before
By the way Laurent is going to give more detail about it quite soon..