Re: indentation, setting variables, commands, and M-x

[Eli Zaretskii <eliz@gnu.org>]

> From: "John M. Gabriele" <john_sips_teaz@yahooz.com>
> Date: Fri, 03 Feb 2006 00:18:20 -0500
> 
> I just read here: http://www.emacswiki.org/cgi-bin/wiki/NoTabs
> that I can add this
> 
>      (setq-default indent-tabs-mode nil)
> 
> to my .emacs file (which I haven't yet created). That page says
> I can "customize the indent-tabs-mode variable". What does that
> mean exactly? How do I go about "customizing" it?

Customizing a variable means do exactly what you are about to do: add
a line to your .emacs that sets the variable to some value.

The line above is actually Lisp code.  If you want to avoid adding
Lisp to your .emacs yourself, or if some variable needs tricky
customization that your Lisp is not good enough to master, try the
"M-x customize" interface, which will present a buffer with clickable
buttons and then write the necessary Lisp for you.  For example, "M-x
customize-variable RET indent-tabs-mode RET" will do that for the
variable you want.

> I'm also curious: what's the translation between adding the
> above line to my .emacs, and typing something in while editing
> (presumably "M-x something")? That is, if someone tells me a
> line to add to my .emacs file, how can I figure out how to do
> the same thing from within the editor while editing?

The easiest way to do that is type the necessary stuff into your
.emacs, and then evaluate it.  For a single parenthesized expression,
go to the closing right paren and type "C-x C-e".  For several
expressions, do this for each expression in turn.

> Continuing with the indentation issue, I read here:
> http://www.emacswiki.org/cgi-bin/wiki/IndentationBasics that
> there's a number of "variables" I can set. I see "tab-width"
> there. Yay! That looks like what I want. :)

It isn't, most probably, not if you wish to code in C/C++.  For those
languages, the indentation system is very elaborate, so the way to
customize it is to use the interactive procedure explained in the CC
Mode manual.  Type "C-h i m CC mode RET", then "g Interactive RET",
and you will be looking at that explanation.  (This invokes the Info
mode that is a mode to read on-line manuals.  If you aren't yet
familiar with Info, take a few minutes to do so, since a complex
system such as Emacs is impossible to use efficiently without knowing
how to take advantage of its elaborate documentation.)

> But, again, how
> do I "set a variable" for emacs (both in my .emacs file,
> and live, while editing)?

See above.  In addition, for a single variable with a simple value,
typing "M-x set-variable RET indent-tabs-mode RET nil RET" will do
what you want.