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(加载“file.scm”)在Scheme的新环境中

发布于 2024-10-24 08:10:07 字数 341 浏览 1 评论 0原文

MIT Scheme 的 (load ...) 过程显然接受环境作为参数。有什么方法可以“克隆”当前环境并将其传递到那里，以便我可以将文件的环境与我自己的环境隔离？

（我看过这里但是我什么也没发现……）

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娇俏 2024-10-31 08:10:07

像这样的事情怎么样？

(define (clone-env env)
  (let ((bindings (environment-bindings env)))
    (make-top-level-environment (map car bindings)
                                (map cadr bindings))))

1 ]=> (define foo 1)

;Value: foo

1 ]=> (eq? (the-environment) (clone-env (the-environment)))

;Value: #f

编辑添加：

我不太确定你想做什么，但这就是我为测试上述内容所做的事情。我创建了一个文件 foo.scm 包含：

(set! foo 2)
(define baz (+ foo foo))
baz

然后，

1 ]=> (define foo 1)

;Value: foo

1 ]=> (load "foo.scm" (clone-env (the-environment)))

;Loading "foo.scm"... done
;Value: 4

1 ]=> foo

;Value: 1

1 ]=> baz

;Unbound variable: baz
;To continue, call RESTART with an option number:
; (RESTART 3) => Specify a value to use instead of baz.
; (RESTART 2) => Define baz to a given value.
; (RESTART 1) => Return to read-eval-print level 1.

2 error>

How about something like this ?

(define (clone-env env)
  (let ((bindings (environment-bindings env)))
    (make-top-level-environment (map car bindings)
                                (map cadr bindings))))

1 ]=> (define foo 1)

;Value: foo

1 ]=> (eq? (the-environment) (clone-env (the-environment)))

;Value: #f

Edited to add:

I'm not exactly sure what you are trying to do, but here's what I did to test the above. I created a file foo.scm containing:

(set! foo 2)
(define baz (+ foo foo))
baz

Then,

1 ]=> (define foo 1)

;Value: foo

1 ]=> (load "foo.scm" (clone-env (the-environment)))

;Loading "foo.scm"... done
;Value: 4

1 ]=> foo

;Value: 1

1 ]=> baz

;Unbound variable: baz
;To continue, call RESTART with an option number:
; (RESTART 3) => Specify a value to use instead of baz.
; (RESTART 2) => Define baz to a given value.
; (RESTART 1) => Return to read-eval-print level 1.

2 error>

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