(交互式)在Emacs Lisp函数中意味着什么？

Question

Emacs Lisp函数通常像这样开始:

(lambda () (interactive) ...

"(互动)"有什么作用？

Answer 1

只是为了澄清(它在Charlie引用的引用文档中)(interactive)不仅适用于键绑定函数,而且适用于任何函数.没有(interactive),它只能以编程方式调用,而不能从M-x(或通过键绑定)调用.

编辑:请注意,只是将"(交互式)"添加到函数中并不一定会使它以这种方式工作 - 可能有很多原因函数不是交互式的.范围,依赖关系,参数等

Answer 2

我的意思是你要包含一些代码,用于在绑定到键时使函数可调用所需的东西 - 比如从CTRL-u获取参数.

看看CTRL-h f interactive细节:

    interactive is a special form in `C source code'.
    (interactive args)

    Specify a way of parsing arguments for interactive use of a function.
    For example, write
      (defun foo (arg) "Doc string" (interactive "p") ...use arg...)
    to make ARG be the prefix argument when `foo' is called as a command.
    The "call" to `interactive' is actually a declaration rather than a function;
     it tells `call-interactively' how to read arguments
     to pass to the function.
    When actually called, `interactive' just returns nil.

    The argument of `interactive' is usually a string containing a code letter
     followed by a prompt.  (Some code letters do not use I/O to get
     the argument and do not need prompts.)  To prompt for multiple arguments,
     give a code letter, its prompt, a newline, and another code letter, etc.
     Prompts are passed to format, and may use % escapes to print the
     arguments that have already been read.

Answer 3

更值得一提的是,这interactive是交互式上下文中的主要目的(例如,当用户使用键绑定调用函数时)让用户指定函数参数,否则只能以编程方式给出.

例如,考虑函数sum返回两个数字的总和.

(defun sum (a b)
  (+ a b))

您可以调用它,(sum 1 2)但只能在Lisp程序(或REPL)中执行.如果interactive在函数中使用特殊形式,则可以询问用户参数.

(defun sum (a b)
  (interactive
   (list
    (read-number "First num: ")
    (read-number "Second num: ")))
  (+ a b))

现在M-x sum让你在迷你缓冲区中键入两个数字,你仍然可以这样做(sum 1 2).

interactive 如果交互式调用函数,则应返回一个列表,该列表将用作参数列表.