如何在elisp中返回函数 [英] how to return function in elisp

问题描述

这与此问题有关:将省略号函数作为参数和参数返回值

(defun avg-damp (n)
   '(lambda(x) (/ n 2.0)))

任何一个

(funcall (avg-damp 6) 10)

或

((avg-damp 6) 10)

他们分别给出了Symbol's value as variable is void: n和eval: Invalid function: (avg-damp 6)的错误.

They gave errors of Symbol's value as variable is void: n and eval: Invalid function: (avg-damp 6) respectively.

推荐答案

第一种形式不起作用的原因是n是动态绑定的，而不是按词法绑定的:

The reason the first form does not work is that n is bound dynamically, not lexically:

(defun avg-damp (n)
  (lexical-let ((n n))
    (lambda(x) (/ x n))))
(funcall (avg-damp 3) 12)
==> 4

第二种形式不起作用的原因是Emacs Lisp与Common Lisp一样，

The reason the second form does not work is that Emacs Lisp is, like Common Lisp, a "lisp-2", not a "lisp-1"

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