rectangular¶

(define (install-rectangular-package)
    ;; internal procedures
    (define (real-part z) (car z))
    (define (imag-part z) (cdr z))
    (define (make-from-real-imag x y) (cons x y)) 
    (define (magnitude z)
        (sqrt (+ (square (real-part z))
                 (square (imag-part z)))))
    (define (angle z)
        (atan (imag-part z) (real-part z)))
    (define (make-from-mag-ang r a)
        (cons (* r (cos a)) (* r (sin a))))
    ;; interface to the rest of the system
    (define (tag x) (attach-tag 'rectangular x))
    (put 'real-part '(rectangular) real-part)
    (put 'imag-part '(rectangular) imag-part)
    (put 'magnitude '(rectangular) magnitude)
    (put 'angle '(rectangular) angle)
    (put 'make-from-real-imag 'rectangular
         (lambda (x y) (tag (make-from-real-imag x y))))
    (put 'make-from-mag-ang 'rectangular
         (lambda (r a) (tag (make-from-mag-ang r a))))
    'done)

(install-rectangular-package)