Variables indent-tabs-mode and tab-always-indent

Variables indent-tabs-mode and tab-always-indent

[carlmarcos--- via Users list for the GNU Emacs text editor]

Have encountered two variables, namely `indent-tabs-mode` and `tab-always-indent`.

There is adequate information about `tab-always-indent`.  Documentation for variable `indent-tabs-mode` states "Indentation can insert tabs if this is non-nil".

How do these two variables work together, and do they conflict?

Re: Variables indent-tabs-mode and tab-always-indent

[Eli Zaretskii]

> Date: Sun, 19 Jun 2022 06:12:54 +0200 (CEST)
> From: carlmarcos--- via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>
> 
> 
> Documentation for variable `indent-tabs-mode` states "Indentation can insert tabs if this is non-nil".
> 
> How do these two variables work together

When the value of tab-always-indent and the situation in which you
press the TAB key are such that Emacs decides to indent the line,
indent-tabs-mode controls whether Emacs inserts just spaces or a muix
of TABs and spaces.

> and do they conflict?

No.

Re: Variables indent-tabs-mode and tab-always-indent

[carlmarcos--- via Users list for the GNU Emacs text editor]

Jun 19, 2022, 06:10 by eliz@gnu.org:

>> Date: Sun, 19 Jun 2022 06:12:54 +0200 (CEST)
>> From: carlmarcos--- via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>
>>
>>
>> Documentation for variable `indent-tabs-mode` states "Indentation can insert tabs if this is non-nil".
>>
>> How do these two variables work together
>>
>
> When the value of tab-always-indent and the situation in which you
> press the TAB key are such that Emacs decides to indent the line,
> indent-tabs-mode controls whether Emacs inserts just spaces or a muix
> of TABs and spaces.
>
Does this mean that `tab-always-indent` is just about what happens when the tab key is used;
whilst `indent-tabs-mode` is concerned about the indentation style of whether to use tab or spaces? 

>> and do they conflict?
>>
>
> No.
>
Do you recommend to enable both?  The variable `indent-tabs-mode` does not say what it uses as default.

Re: Variables indent-tabs-mode and tab-always-indent

[Eli Zaretskii]

> Date: Sun, 19 Jun 2022 15:06:40 +0200 (CEST)
> From: carlmarcos@tutanota.com
> Cc: help-gnu-emacs@gnu.org
> 
>  When the value of tab-always-indent and the situation in which you
>  press the TAB key are such that Emacs decides to indent the line,
>  indent-tabs-mode controls whether Emacs inserts just spaces or a muix
>  of TABs and spaces.
> 
> Does this mean that `tab-always-indent` is just about what happens when the tab key is used;
> whilst `indent-tabs-mode` is concerned about the indentation style of whether to use tab or spaces? 

Yes, exactly.

>  and do they conflict?
> 
>  No.
> 
> Do you recommend to enable both?

That depends on the major mode and its conventions, as well as on your
preferences, and whether you intend to exchange your files with people
who use other editors.

> The variable `indent-tabs-mode` does not say what it uses as default.

It does here:

  indent-tabs-mode is a variable defined in ‘src/indent.c’.

  Its value is nil
  Original value was t    <<<<<<<<<<<<<<<<<<<<<<<<<<<
  Local in buffer shr.el; global value is t