[roywiggins]

They built their MUMPS IDE themselves, and their change tracking / bug management system. And effectively the database code is also entirely written by Epic- the business logic and database are both written in MUMPS and live side-by-side.

So they have quite a lot on their plate when it comes to tooling. When I was there, there was a truly horrible attempt at a DSL for code-generation that would build database querying code, but I found it both unwritable and unreadable.