Created
August 29, 2012 03:25
-
-
Save wakita/3506509 to your computer and use it in GitHub Desktop.
マクロ定義を環境に埋め込み,取り出す試み → でも失敗
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
;;; マクロ使用をマークするためのシンボル | |
(define jsx-mark-macro-usage | |
(string->symbol "JSX:Mark Macro Usage")) | |
;;; マクロ使用を環境に閉じ込めるための仕掛け | |
(define (encapsulate e) | |
`(,jsx-mark-macro-usage (lambda () ,e '()))) | |
;;; encapsulate でマクロ使用を閉じ込めた箇所から,展開後の式を取り出す | |
(define (extract e) | |
(define env '()) | |
(define (aux e) | |
(cond | |
((null? e) e) | |
((and (list? e) (eq? (car e) 'define)) | |
(let* ((var (cadr e)) | |
(e (caddr e))) | |
(set! env (cons `(,var . ,e) env)) | |
`(define ,var ,(aux e)))) | |
((and (list? e) (eq? (car e) jsx-mark-macro-usage)) | |
(cadddr (assq (cadr e) env))) | |
((list? e) (map (lambda (e) (aux e)) e)) | |
(#t e))) | |
(aux e)) | |
;; ここから実験.まずは A.S. のマクロ定義 | |
(define-syntax def | |
(syntax-rules () | |
((_ var val) (define var val)))) | |
;; (def v a) を encapsulate で lambda 環境に閉じ込めてからマクロ展開し,最後に extract を使って lambda 環境から解放してみた. | |
(let* ((e0 '(def v a)) | |
(e1 (macro-expand (encapsulate e0))) | |
(e2 (extract e1))) | |
(display "An expression\n") | |
(pretty-print e0) (display "\n\nExpands to \n") | |
(pretty-print e1) (display "\n\nand becomes\n") | |
(pretty-print e2) (newline)) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
いくつか問題があります.
ということで,別の方法を考えないといけないようです.