提供emacs交互功能：之前 [英] Advising an emacs interactive function: before

问题描述

我想提前咨询一些使用交互式参数的功能，例如 find-dired ：

 （defadvice find-dired（before eab- find-dired activate）
（消息before！）
（setq find-args'（-iname'**'10）））
  

但是，emacs仅在 find-dired 交互式会话后执行此建议，我无法设置 find-args 之前。如何解决矛盾？

更新。请注意， defadvice 宏是 deprecated 。

解决方案

artscan 用可行的答案回答了自己的问题，但有点不完整和误导。这也涉及 'interactive ，这可能会混淆在一起，因为它看起来像在命令的正文内部定义，但实际上是在之前使用的功能是输入 - 在执行任何建议之前（除非该建议具有'交互式调用...）

a href =http://www.gnu.org/software/emacs/manual/html_mono/elisp.html#Combined-Definition =nofollow noreferrer>文档的建议缺少一些细节，在这种情况下会有所帮助，所以看起来更好的地方实际上是来源： advice.el 。看看，并找到评论部分 @ Foo游戏：建议教程。您也可以使用 Mx find-library advice RET 在Emacs中找到源代码。

具体来说，对于这个问题，在 advice.el 标签为 @@提供互动行为： - 因为这正是你想要做的。 / p>

如果仔细阅读，您会发现建议不需要以 / code>，但也可以之前的，并且可以在之后 - 虽然这只是问为了麻烦这是因为交互式是（并且必须被）特别处理。





所以，以下代码工作（请注意之前的）：

 （defadvice find-dired -find-dired（dir args）activate）
ignore find-args，hard code \-iname'**'\
（interactive 
（list目录名在目录中运行find：nilt）
（read-string运行find（with args）：'（-iname'**'10）
' （find-args-history。1））））））
  

正如其他人建议的，正在编写自己的功能，我认为最简单的是 Lindydancer 的answer 。

建议是一个非常诱人的工具，但容易过度使用。我不会说这是危险的，但应该谨慎使用。在编写自己的函数不起作用时，似乎最好用 - 例如，改变不能修改的代码调用的函数的行为。我认为这种情况的很好的例子可以在这里，这里和这里（嘟嘟我自己的角）。

I want to before-advice some function, which uses interactive arguments, e.g. find-dired:

(defadvice find-dired (before eab-find-dired activate)
  (message "before!")
  (setq find-args '("-iname '**'" . 10)))

But emacs executes this advice only after find-dired interactive session and I can't setup find-args before. How to resolve the contradiction?

Upd. Note that defadvice macro is deprecated.

解决方案

artscan answered his own question with a workable answer, but it's a bit incomplete and misleading. This also involves 'interactive, which can be confusing in and of itself - in that it looks like it is defined inside the body of the command, but is actually used before the function is entered - and before any advice is executed (unless that advice has 'interactive calls...)

The documentation for advice lacks a number of details that would help in this situation, so the better place to look is actually the source: advice.el. Look at that and find the comment section @ Foo games: An advice tutorial. You can also find the source in your Emacs itself with M-x find-library advice RET.

Specifically, for this problem, look at the section in advice.el labeled @@ Advising interactive behavior: - because that's exactly what you're trying to do.

If you read it closely, you'll notice that the advice does not need to be of the form around, but can be before as well, and it can be after - though that's just asking for trouble. This is because the interactive is (and has to be) treated special.

So, the following code works (note the before):

(defadvice find-dired (before eab-find-dired (dir args) activate)
  "ignore find-args, hard code \"-iname '**'\""
  (interactive
   (list (read-directory-name "Run find in directory: " nil "" t)
         (read-string "Run find (with args): " '("-iname '**'" . 10)
                      '(find-args-history . 1)))))

Probably a cleaner way to do this, as others suggested, is writing your own function, and I think the easiest is Lindydancer's answer.

Advice is a pretty enticing tool, but is easy to overuse. I wouldn't go as far as saying it is dangerous, but should be used sparingly. It seems to be best used when writing your own function doesn't work - for instance, changing the behavior of a function that is called by code you can't modify. I think good examples of this situation can be found here, here, and here (to toot my own horn).

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