> ... like putting together a puzzle It's funny how lots of good formalisms, notations, and DSLs all achieve this quality in different ways. In particular, th

> ... like putting together a puzzle It's funny how lots of good formalisms, notations, and DSLs all achieve this quality in different ways. In particular, this reminds me of the mathematics of tensors, or Bra-Ket notation in QM. Both of these systems use notation to give each piece of the puzzle a particular shape, so that if you know all of the pieces you can often see immediately how they should fit together. This seems (to me) to be the most important part of designing an API, and the brilliant strength of a good type system is that you get this quality for free.