plp/scheme/scheme1.rkt

#lang racket
(let ((x 2)
      (y 3))
  (let ((f (lambda () (+ (* x x) (* y y)))))
    (let ((x 5)
          (y 7))
     (f))))

(let ((x 1)
      (y 2))
  (let ((x y)
        (y x))
    (begin
      (display x)
      (newline)
      (display y)
      (newline))))

(let ((x (quasiquote (+ 1 (unquote (+ 1 1)) 3))))
  x)

(begin
  (define x 23)
  (set! x 42)
  x)

(define (k . j) j)
(k 1 2 3)
(apply + '(1 2 3))