Question

In Scheme, how can I make use of the define/lambda shorthand for nested lambda expressions within my define?

For example given the following procedure…

(define add
  (lambda (num1 num2)
    (+ num1 num2)))

One can shorten it to this:

(define (add num1 num2)
  (+ num1 num2))

However, how can I shorten the following function similarly ?

(define makeOperator
  (lambda (operator)
    (lambda (num1 num2)
      (operator num1 num2))))

;example useage - equivalent to (* 3 4):
((makeOperator *) 3 4)

Answer 1

(define (makeOperator operator)
  (lambda (num1 num2)
    (operator num1 num2)))

The second lambda can not be shortened.

Well you could shorten it to (define (makeOperator operator) operator), if you don’t want to enforce that the returned function takes exactly two arguments.