MPS looks like awsome system. From what I understand, there is no parser generator, so defined languages must be entered only inside of the MPS editor, correct? I'm trying to understand how this is generally useful from a toolchain perspective - if I can't generate my defined language in text via external tools, integrate transformation into a build process, etc.
Also an issue is the Java-centricity and the need to extend a language in order to generate it (if I understand correctly.)
Though I'd of course rather have a free tool, we are looking for a suitable MP tool (including the use of the projectional editor), and would gladly pay well for a commercial product with a suitable feature-set. I apologize ahead of time for any misconceptions.