Using backward-char non-interactively

Using backward-char non-interactively

[Marcin Borkowski]

Hi,

is it ok to use backward-char in elisp programs assuming that I did
check that I'm not at beginning of buffer?  Or is it better to use
(goto-char (1- point)) or something like that?  Or maybe it doesn't
matter?  ("Better" may be in terms of style, speed, or side effects,
like cluttering the *Messages* buffer.)

TIA,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Adam Mickiewicz University

Re: Using backward-char non-interactively

[Barry Margolin]

In article <mailman.10751.1388498331.10748.help-gnu-emacs@gnu.org>,
 Marcin Borkowski <mbork@wmi.amu.edu.pl> wrote:

> Hi,
> 
> is it ok to use backward-char in elisp programs assuming that I did
> check that I'm not at beginning of buffer?  Or is it better to use
> (goto-char (1- point)) or something like that?  Or maybe it doesn't
> matter?  ("Better" may be in terms of style, speed, or side effects,
> like cluttering the *Messages* buffer.)

Most command functions are OK to use in programs. The handful that 
shouldn't say something in their documentation string, usually with a 
pointer to an alternative function that's better.

-- 
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***

Re: Using backward-char non-interactively

[Emanuel Berg]

Barry Margolin <barmar@alum.mit.edu> writes:

> Most command functions are OK to use in programs. The
> handful that shouldn't say something in their
> documentation string, usually with a pointer to an
> alternative function that's better.

Example, `beginning-of-buffer':

> Don't use this command in Lisp programs!
> (goto-char (point-min)) is faster.

-- 
underground experts united:
http://user.it.uu.se/~embe8573

Re: Using backward-char non-interactively

[Andreas Röhler]

Am 31.12.2013 14:58, schrieb Marcin Borkowski:
> Hi,
>
> is it ok to use backward-char in elisp programs assuming that I did
> check that I'm not at beginning of buffer?  Or is it better to use
> (goto-char (1- point)) or something like that?  Or maybe it doesn't
> matter?  ("Better" may be in terms of style, speed, or side effects,
> like cluttering the *Messages* buffer.)
>
> TIA,
>

Hi,

answer depends from the case.

In general it's okay.
If you must avoid any messages, would use (unless (bobp)

Here a from to try it:

(funcall (lambda ()(goto-char 1)(unless (bobp)(backward-char))))