From: Stefan Monnier <monnier@IRO.UMontreal.CA>
To: Drew Adams <drew.adams@oracle.com>
Cc: emacs-devel@gnu.org
Subject: Re: 1) (elisp) `Advising Named Functions', 2) search filtering example
Date: Mon, 17 Oct 2016 15:25:05 -0400 [thread overview]
Message-ID: <jwvk2d6ssal.fsf-monnier+Inbox@gnu.org> (raw)
In-Reply-To: <e05d2762-9d76-4349-a222-d16e35c19197@default> (Drew Adams's message of "Mon, 17 Oct 2016 11:41:56 -0700 (PDT)")
> That's one interpretation. There is no mention of the fact that
> the hook it is talking about is necessarily a "multiple-function
> hook" that happens to have a single function as value.
That's because you misunderstand its doc. The confusion comes from the
multiple uses of the name "hook". There are basically two uses of
the word "hook" in the context of Emacs:
- a very generic sense, which refers to some kind of way to influence
the behavior of something. Used also sometimes as a verb "you can
hook directly into ..." which might be used even in cases where the
"hooking" is done by modifying some chunk of code. Sometimes
"hook" is even used to just mean a customization point ("that package
doesn't give me any hook to specify which char to insert").
- a specific sense, which refers to an "object" implemented as a symbol
where the symbol-value slot holds a list of functions (and the "hook"
is really the symbol, not the list of functions, because we can also use
its various buffer-local values).
The second subsumes the first.
So *-function is a hook in the first sense but not in the second.
Whereas *-functions and *-hook are hooks in both senses.
add-hook and remove-hook only apply to hooks in the second sense.
The advice mechanism treats every symbol's function definition as a hook
(in the first sense), whether the author intended it that way (as is the
case for `ask-user-about-supersession-threat') or not.
Stefan
next prev parent reply other threads:[~2016-10-17 19:25 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-17 5:25 1) (elisp) `Advising Named Functions', 2) search filtering example Drew Adams
2016-10-17 12:20 ` Noam Postavsky
2016-10-17 14:02 ` Drew Adams
2016-10-17 14:37 ` Noam Postavsky
2016-10-17 14:52 ` Stefan Monnier
2016-10-17 15:40 ` Drew Adams
2016-10-17 15:51 ` Stefan Monnier
2016-10-17 17:05 ` Drew Adams
2016-10-17 17:47 ` Stefan Monnier
2016-10-17 15:40 ` Drew Adams
2016-10-17 16:16 ` Noam Postavsky
2016-10-17 17:05 ` Drew Adams
2016-10-17 17:53 ` Stefan Monnier
2016-10-17 18:41 ` Drew Adams
2016-10-17 19:25 ` Stefan Monnier [this message]
2016-10-18 19:47 ` Richard Stallman
2016-10-19 6:15 ` Eli Zaretskii
2016-10-19 20:00 ` Richard Stallman
2016-10-19 20:18 ` Stefan Monnier
2016-10-20 7:17 ` Eli Zaretskii
2016-10-20 7:06 ` Eli Zaretskii
2016-10-20 18:06 ` Richard Stallman
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