* Meaning of the hash character
@ 2008-11-20 13:35 Nordlöw
2008-11-20 14:16 ` Juanma Barranquero
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Nordlöw @ 2008-11-20 13:35 UTC (permalink / raw)
To: help-gnu-emacs
I have long wondered about the meaning of the hash character # in
emacs lisp.
Here is an example taken from hl-line.el
(add-hook 'change-major-mode-hook #'hl-line-unhighlight nil t)
What effect does it have?
/Nordlöw
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Meaning of the hash character
2008-11-20 13:35 Meaning of the hash character Nordlöw
@ 2008-11-20 14:16 ` Juanma Barranquero
2008-11-20 17:45 ` Barry Margolin
2008-11-20 20:39 ` Nikolaj Schumacher
2 siblings, 0 replies; 4+ messages in thread
From: Juanma Barranquero @ 2008-11-20 14:16 UTC (permalink / raw)
To: Nordlöw; +Cc: help-gnu-emacs
On Thu, Nov 20, 2008 at 14:35, Nordlöw <per.nordlow@gmail.com> wrote:
> I have long wondered about the meaning of the hash character # in
> emacs lisp.
From the "Anonymous Functions" node of the Emacs Lisp Reference:
The read syntax `#'' is a short-hand for using `function'. For
example,
#'(lambda (x) (* x x))
is equivalent to
(function (lambda (x) (* x x)))
-- Special Form: function function-object
This special form returns FUNCTION-OBJECT without evaluating it.
In this, it is equivalent to `quote'. However, it serves as a
note to the Emacs Lisp compiler that FUNCTION-OBJECT is intended
to be used only as a function, and therefore can safely be
compiled. Contrast this with `quote', in *Note Quoting::.
*Note describe-symbols example::, for a realistic example using
`function' and an anonymous function.
Juanma
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Meaning of the hash character
2008-11-20 13:35 Meaning of the hash character Nordlöw
2008-11-20 14:16 ` Juanma Barranquero
@ 2008-11-20 17:45 ` Barry Margolin
2008-11-20 20:39 ` Nikolaj Schumacher
2 siblings, 0 replies; 4+ messages in thread
From: Barry Margolin @ 2008-11-20 17:45 UTC (permalink / raw)
To: help-gnu-emacs
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 642 bytes --]
In article
<15d554aa-7f1c-45e5-a26f-017bd6258140@d32g2000yqe.googlegroups.com>,
Nordlöw <per.nordlow@gmail.com> wrote:
> I have long wondered about the meaning of the hash character # in
> emacs lisp.
>
> Here is an example taken from hl-line.el
> (add-hook 'change-major-mode-hook #'hl-line-unhighlight nil t)
>
> What effect does it have?
>
> /Nordlöw
#' is to 'function' as ' is to 'quote', i.e.
'foo ==> (quote foo)
#'foo ==> (function foo)
--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
*** PLEASE don't copy me on replies, I'll read them in the group ***
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Meaning of the hash character
2008-11-20 13:35 Meaning of the hash character Nordlöw
2008-11-20 14:16 ` Juanma Barranquero
2008-11-20 17:45 ` Barry Margolin
@ 2008-11-20 20:39 ` Nikolaj Schumacher
2 siblings, 0 replies; 4+ messages in thread
From: Nikolaj Schumacher @ 2008-11-20 20:39 UTC (permalink / raw)
To: Nordlöw; +Cc: help-gnu-emacs
Nordlöw <per.nordlow@gmail.com> wrote:
> I have long wondered about the meaning of the hash character # in
> emacs lisp.
>
> Here is an example taken from hl-line.el
> (add-hook 'change-major-mode-hook #'hl-line-unhighlight nil t)
>
> What effect does it have?
From the manual:
We sometimes write `function' instead of `quote' when quoting the name
of a function, but this usage is just a sort of comment:
(function SYMBOL) == (quote SYMBOL) == 'SYMBOL
The read syntax `#'' is a short-hand for using `function'.
regards,
Nikolaj Schumacher
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2008-11-20 20:39 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-11-20 13:35 Meaning of the hash character Nordlöw
2008-11-20 14:16 ` Juanma Barranquero
2008-11-20 17:45 ` Barry Margolin
2008-11-20 20:39 ` Nikolaj Schumacher
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).