PLT 方案：转换“Casting SPELs in LISP”中的宏之一

发布于 2024-08-17 04:35:59 字数 549 浏览 5 评论 0原文

    (defspel game-action (command subj obj place &rest rest)
  `(defspel ,command (subject object)
     `(cond ((and (eq *location* ',',place)
                  (eq ',subject ',',subj)
                  (eq ',object ',',obj)
                  (have ',',subj))
             ,@',rest)
            (t '(i cant ,',command like that.)))))

这是来自 http://www.lisperati.com/actions.html 的代码 '宏定义宏'。我似乎无法将其适当地转换为方案。有人可以向我解释一下在Scheme中创建同样的东西的过程吗？

原文

    (defspel game-action (command subj obj place &rest rest)
  `(defspel ,command (subject object)
     `(cond ((and (eq *location* ',',place)
                  (eq ',subject ',',subj)
                  (eq ',object ',',obj)
                  (have ',',subj))
             ,@',rest)
            (t '(i cant ,',command like that.)))))

Thats the code from http://www.lisperati.com/actions.html for the 'macro defining macro'. I can't seem to convert it appropriately to scheme. Can someone explain to me the process of creating this same sort of thing in Scheme?

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私野 2024-08-24 04:35:59

这种宏实际上在Scheme中要简单得多，因为您可以使用define-syntax-rule来完成这一切（在标准Scheme代码中，您将需要define-syntax + <代码>语法规则）。你基本上做同样的事情，减去整个引用/取消引用的混乱。

(defspel (game-action command subj obj place rest ...)
  (defspel (command subject object)
    (cond [(and (eq? *location* 'place)
                (eq? 'subject 'subj)
                (eq? 'object 'obj)
                (have 'subj))
           rest ...]
          [else '(i cant command like that.)])))

由于这实际上是大部分代码，因此我将整个代码移植到 PLT - 请参阅在邮件列表上发布。

This kind of macro is actually much simpler in Scheme, since you can do it all with define-syntax-rule (in standard Scheme code you will need define-syntax + syntax-rules). You basically do the same thing, minus the whole quote/unquote mess.

(defspel (game-action command subj obj place rest ...)
  (defspel (command subject object)
    (cond [(and (eq? *location* 'place)
                (eq? 'subject 'subj)
                (eq? 'object 'obj)
                (have 'subj))
           rest ...]
          [else '(i cant command like that.)])))

And since this is actually most of the code, I ported the whole thing to PLT -- see the post on the mailing list.

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