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问题描述

我安装的一些elisp函数生成警告:

Some elisp functions that I have installed generate warnings:

`flet' is an obsolete macro (as of 24.3); use either `cl-flet' or `cl-letf'.

如果我只是将所有 flet cl-flet
如果可以替换它们,哪一个更好?

Is it dangerous if I simply replace all flet with cl-flet?If it is OK to replace them, which one is better?

如果更换它不是危险的,我会将拉请求发送到项目

If it is not dangerous to replace it, I'd send pull requests to the projects.

有没有理由不改变它?

推荐答案

flet cl-flet cl-letf不同
这更危险(也许更强大)。这就是为什么它被废弃了。

flet isn't the same as either cl-flet or cl-letf.It's more dangerous (and maybe more powerful). That's why it's being deprecated.

由于它是不同的(动态绑定一个函数名称),你必须考虑
在每种情况下,如果适合替换它 cl-flet

Since it's different (binds dynamically a function name), you have to thinkin each case if it's appropriate to replace it with cl-flet.

(defun adder (a b)
  (+ a b))

(defun add-bunch (&rest lst)
  (reduce #'adder lst))

(add-bunch 1 2 3 4)
;; 10

(flet ((adder (a b) (* a b)))
  (add-bunch 1 2 3 4))
;; 24

(cl-flet ((adder (a b) (* a b)))
  (add-bunch 1 2 3 4))
;; 10

请注意, cl-flet 绑定,所以加法器的行为没有改变,
flet 做动态绑定 add-bunch 暂时产生阶乘。

Note that cl-flet does lexical binding, so the behavior of adder isn't changed,while flet does dynamic binding, which makes add-bunch temporarily produce a factorial.

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09-26 12:20