If you want to invest a bit in the learning curve, have a look at the free JetBrains MPS (meta programming system): it is a proper language workbench for exactl

If you want to invest a bit in the learning curve, have a look at the free JetBrains MPS (meta programming system): it is a proper language workbench for exactly that. Itemis, the company behind xtext, is now using MPS. It supports composable languages and provides IDEs for the language you created with code completion etc. It is complex, though, so it takes a while to learn.