New Code, DSL first design

I just started writing some new code for a project and for the first time I started with the DSL first, and I liked it.

In Martin Fowlers article http://martinfowler.com/articles/mocksArentStubs.html he talks about middle-out design, start with a feature in the domain layer and work, or top-down where you start with the UI and, work down.

For me a DSL is another way a user can interact / configure a system so it seems related to but, different than a traditional UI. I think it's a closer abstraction to the domain than the UI, but you can easily imagine anything you do in a DSL you could do in the UI. So in a sense designing DSL first is a top-down approach, but in my very limited experience it's so close to the domain model, that it really feels like a middle-out approach.

Anyway, it was a really interesting experience and let me think about what features I needed in my domain layer very easily. And because I was playing with so many syntaxes I finally settled on something that let me loosen up the design quite a bit more than I would have if I had started in the domain layer first.