answer M-99 written in Scheme

gistfile1.sls

;; http://common-lisp-users.jp/index.cgi?M-99

(define-syntax inc1
  (syntax-rules ()
    ((_ v)
     (set! v (+ v 1)))))

(define-syntax when
  (syntax-rules ()
    ((_ p b0 b1 ...)
     (if p (begin b0 b1 ...)))))

(define-syntax unless
  (syntax-rules ()
    ((_ p b0 b1 ...)
     (when (not p) b0 b1 ...))))

(define-syntax while
  (syntax-rules ()
    ((_ p b0 b1 ...)
     (let loop () (when p (begin b0 b1 ... (loop)))))))

(define-syntax until
  (syntax-rules ()
    ((_ p b0 b1 ...)
     (while (not p) b0 b1 ...))))

(define-syntax do-forever
  (lambda(stx)
    (syntax-case stx ()
      ((k b0 b1 ...)
       (with-syntax ((return (datum->syntax #'k 'return)))
         #'(call/cc (lambda(return) (while #t b0 b1 ...))))))))

(define-syntax inc
  (syntax-rules ()
    ((_ v n)
     (set! v (+ v n)))))
    ((_ v)
     (inc1 v))

(define-syntax my-and
  (syntax-rules ()
    ((_ x) x)
    ((_ x r ...)
     (if x (my-and r ...) #f))))

(define-syntax my-or
  (syntax-rules ()
    ((_ x) x)
    ((_ x r ...)
     (let ((t x))
       (if t t (my-or r ...))))))

(define-syntax my-let
  (syntax-rules ()
    ((_ ((v e) ...) b0 b1 ...)
     ((lambda(v ...) b0 b1 ...) e ...))))

(define-syntax my-let*
  (syntax-rules ()
    ((_ ((v e)) body ...)
     ((lambda(v) body ...) e))
    ((_ ((v e) r ...) b0 b1 ...)
     ((lambda(v) (my-let* (r ...) b0 b1 ...)) e))))

(define-syntax my-cond
  (syntax-rules ()
    ((_ (p e ...))
     (if p (begin e ...)))
    ((_ (p e ...) r ...)
     (if p (begin e ...) (my-cond r ...)))))

(define-syntax psetq
  (syntax-rules ()
    ((_ r ...)
     (letrec-syntax ((%%psetq
                      (syntax-rules ()
                        ((_ (v f n) (... ...))
                         (let ((n f) (... ...)) (set! v n) (... ...)))))
                     (%psetq
                      (syntax-rules ()
                        ((_ (a (... ...)))
                         (%%psetq a (... ...)))
                        ((_ (a (... ...)) v f e (... ...))
                         (%psetq (a (... ...) (v f n)) e (... ...))))))
       (%psetq () r ...)))))