I was thinking about this topic, and wondering how would a project in MPS be represented on the file system so it can be maintained in some kind of source control?  It seems to me that XML would be the natural way to represent MPS source on disk.  In this case text-diff tools could be replaced by an xml-diff tool.  Or will MPS have diff/merge functionality built-in?

The other question I'm wondering about is how would debugging work?  Will I have to debug the java or C generated under the hood?  Because since DSLs are declarative languages, it would be quite confusing to try to map byte-code instructions to the (possibly multpiple) DSL source(s) that generated this instruction.  So it seems that neither alternative is ideal.

Otto