September 26, 2018
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))
If $b$ is strictly a positive number, the operator expression
(if (> b 0) + -) will evaluate to
+ the result will be $a+b$.
If all other cases, the result will be $a-b$.
In other words, this function compute $a+\left|b\right|$.