1.42

Exercise 1.42: Let f and g be two one-argument functions. The composition f after g is defined to be the function x↦f(g(x)). Define a procedure compose that implements composition. For example, if inc is a procedure that adds 1 to its argument,

((compose square inc) 6)
49

Let's define compose:

(define (compose f g)
    (lambda (x) (f (g x))))

Let's verify the result

(define (inc x) (+ x 1))
(define (square x) (* x x))
((compose square inc) 6)