Representing Financial Contracts

Modern financial contracts are more complex than an immediate subtraction from one account and addition to another account.

Wimpy:

I'd gladly pay you Tuesday for a hamburger today.

Can we represent this formally?

(and (one hamburger)
     (give (zcb tuesday 5 USD)) )

zcb is a zero-coupon bond, i.e. a promise to pay $5 at a future time, Tuesday.

This kind of representation is recursive, allowing complex contracts to be represented with a small set of combinators.