Wed Jan 23 14:39:24 CET 2013
Next interesting question is: how to add an abstract interpretation
that returns new, modified abstract syntax? Autodiff comes to mind.
First, this needs a protocol. How to represent the normal numbers?
Best to just increase arity, i.e.
(x y) -> z -> (x0 x1 y0 y1) -> (z0 z1)
This makes the frontend work. Frontend then maps this double arity
function to the single arity function evaluated over normal number
First however, start with 1-argument functions.