SICP Exercise 1.4

Observe that our model of evaluation allows for combinations whose operators are compound expressions. Use this observation to describe the behavior of the following procedure:

(define (a-plus-abs-b a b)    ((if (> b 0) + -) a b))   

The operation follows on the if a then result, else b where a and b are the + and - operators. This is essentially the old conditional operator in C.