Question

(defmethod! expand-t-setclass (pcset &optional (n 12))
  :icon *PC_ICON*
  :doc "
Given any member of a t-setclass, lists every member of that t-setclass.
The optional parameter N can be used to set the number of equal steps per
octave to something other than the default of 12.

Will tolerate integers out of the mod-N range in PCSET."
  :initvals '((1 3 4) 12)
  :indoc '("pcset or list of them"
           "modulus of the pc space")
  (if (listp (first pcset))
    (expand-t-setclasses pcset)
    (let ((t-prime (t-primeform pcset n)))
      (loop with result = nil
            repeat n
            for x-pcset = pcset then (xpose x-pcset 1 n)
            unless (member x-pcset result) collect x-pcset into result
            finally return result))))


(defmethod! expand-t-setclasses (pcset &optional (n 12))
  (loop for item in pcset collect (expand-t-setclass item n)))

;-----

我对Lisp一般不太熟悉，并试图找到导致此错误的错误：

错误：LOOP中的重复绑定:(结果）

Answer 1

LOOP中有两个表单，引入了一个变量RESULT。

WITH result = nil

和

COLLECT ... INTO result

以上两者都创建了一个变量绑定。

我会用一个将项目推送到RESULT列表的表单替换COLLECT。

(loop ...
      collect item into foo
      ...
      finally (return foo))

到

(loop with foo = nil
      ...
      (push item foo)
      ...
      finally (return (reverse foo)))

您还有其他错误：

FINALLY RETURN result

LOOP语法不支持。最后期望复合形式。

将其替换为：

FINALLY (return result)

RETURN是Common Lisp中定义的宏。

Lisp帮助|错误：LOOP中的重复绑定:(结果）

1 个答案: