mes/syntax.mes

(display "define-syntax...")

(define-macro define-syntax
  (lambda (form expander)
    (expander `(define-macro ,(cadr form)
                 (let ((transformer ,(caddr form)))
                   (lambda (form expander)
                     (expander (transformer form
                                            (lambda (x) x)
                                            eq?)
                               expander))))
              expander)))

(newline)

(display "define-syntax when...")

;; (define-syntax when
;;   (syntax-rules ()
;;     ((when condition exp ...)
;;      (if condition
;;          (begin exp ...)))))

;; (define-macro (when cond exp . rest)
;;   `(if ,cond
;;        (begin ,exp . ,rest)))


(define-macro (when clause . rest)
  (cond
   ((not (eq? clause #f)) (cons 'let (cons '() rest)))))

(define-macro (ifwhen clause . rest)
  (if (not (eq? clause #f)) (cons 'let (cons '() rest))))

(define-macro my-when
  (lambda (test . branch)
    (list 'if test (cons 'begin branch))))

;; (define-macro (q-when test . branch)
;;   `(if ,test
;;        (begin ,@branch)))

;; (define-macro (when clause exp . rest)
;;   (display "all=")
;;   (display  (cons exp rest))
;;   (newline)
;;   `(if ,clause
;;        (begin ,(cons exp rest))))

;; (define-macro (when clause . rest)
;;   (cond
;;    ((not (eq? clause #f)) (cons 'let (cons '() rest)))))

(newline)

(ifwhen #t
  (display "true")
  (newline))

(ifwhen #f
  (display "false")
  (newline)
  '())

(my-when #t
  (display "my-when")
  (newline)
  '())


;; (q-when #t
;;   (display "q-when")
;;   (newline)
;;   '())


(define *gensym* 0)
(define (gensym)
  (set! *gensym* (+ *gensym* 1))
  (string->symbol (string-append "g" (number->string *gensym*))))

(define-macro bla (gensym))

(display bla) (newline)
(display bla) (newline)
(display bla) (newline)

(newline)
'()

;;EOF
EOF2