By the way, there are these things JetBrains MPS and Eclipse Xtext, which are metaprogramming environments, allowing you to define DSLs and actually get IDE sup

By the way, there are these things JetBrains MPS and Eclipse Xtext, which are metaprogramming environments, allowing you to define DSLs and actually get IDE support for features you add. Rather heavyweight compared to just grammar, or to Lisp macros, but apparently you get more in return, seeing as grammar and macros don't teach your editors about the semantics of the new entities.