This sounds like a similar idea to JetBrains' MPS: http://www.jetbrains.com/mps/

The idea with that was that you could provide a structured description of a mini-language and it would be sufficient to generate not only a parser, but also a syntax-highlighting IDE with smart code completion, debugging and other neat features. It looks like they're still developing it too, which is a nice surprise: back when I was still interested in it, it never seemed to have taken off.