Syntax question for experts

Syntax question for experts

[Sébastien Vauban]

Hi,

A quick question...

I've seen both

--8<---------------cut here---------------start------------->8---
(add-hook 'shell-mode-hook
	  (lambda ()
	    (whatever)))
--8<---------------cut here---------------end--------------->8---

and

--8<---------------cut here---------------start------------->8---
(add-hook 'shell-mode-hook
	  '(lambda ()
	     (whatever)))
--8<---------------cut here---------------end--------------->8---

(see the quote in front of lambda).

What is the best writing?  With or without the quote?

By "best", I mean more portable (XEmacs, etc.), or with a longer
life-time (won't become erroneous in a couple of years), etc.

Best regards,
  Seb

-- 
Sébastien Vauban

Re: Syntax question for experts

[Thierry Volpiatto]

Sébastien Vauban <zthjwsqqafhv@spammotel.com> writes:

> Hi,
>
> A quick question...
>
> I've seen both
>
> (add-hook 'shell-mode-hook
> 	  (lambda ()
> 	    (whatever)))
>
> and
>
> (add-hook 'shell-mode-hook
> 	  '(lambda ()
> 	     (whatever)))
>
> (see the quote in front of lambda).
>
> What is the best writing?  With or without the quote?
Without, read that:
http://www.emacswiki.org/cgi-bin/wiki/QuotedLambda

> By "best", I mean more portable (XEmacs, etc.), or with a longer
> life-time (won't become erroneous in a couple of years), etc.
>
> Best regards,
>   Seb

If you want to quote the lambda , quote it like:

,----
| #'(lambda ()...)
`----


that is the same as

,----
| (function (lambda ()...))
`----

 
-- 
A + Thierry
Pub key: http://pgp.mit.edu

Re: Syntax question for experts

[David Hansen]

On Fri, 23 May 2008 08:48:25 +0200 Sébastien Vauban wrote:

> (add-hook 'shell-mode-hook
> 	  (lambda ()
> 	    (whatever)))
>
> and
>
> (add-hook 'shell-mode-hook
> 	  '(lambda ()
> 	     (whatever)))
>
> (see the quote in front of lambda).
>
> What is the best writing?  With or without the quote?

First one is better if you byte compile the code (the quoted expression
isn't byte compiled).  Note that `lambda' is actually a macro that
expands to (function (lambda ...)).

Longer answer here:

http://www.emacswiki.org/cgi-bin/wiki/QuotedLambda

David