Exercises in this lecture   Go to the notes, in which this exercise belongs -- Keyboard shortcut: 'u'   Alphabetic index   Course home   

Exercise solution:
Construction of symbolic expressions


The following is a name binding form with the left and right branch of the structure:

(let ((left (cons (cons 'a 'b) (cons 'c 'd)))
      (right (cons (cons 'e 'f) (cons 'g 'h))))
  (cons left right))

It is, of course, also possible to make one nasty expression with cons'es:

(cons (cons (cons 'a 'b) (cons 'c 'd)) (cons (cons 'e 'f) (cons 'g 'h)))

Please notice the way the Scheme interpreter prints the value of the expression. Try find the rule it applies for printing.