bug#8196: 23.1; Feature request with code: "C-x TAB" to understand tab-stop-list

[Drew Adams <drew.adams@oracle.com>]

> >> I just folded it into indent-rigidly.
> >
> > Dunno what that means exactly, but a priori: too bad. Should be a
> > separate command, as previously discussed and agreed.
> 
> The change has effect only when called interactively and when there is
> no prefix argument. The new feature is more useful.

Yes, we know that.  Please read the thread.  Remember this part, for
instance?

 > > > What you can propose instead is that your new command get the
 > > > traditional binding for `indent-rigidly', `C-x TAB'. What we
 > > > should not do is replace the current `indent-rigidly' behavior
 > > > by the proposed behavior in the same command. Steal the key,
 > > > perhaps, but not the command.
 > >
 > > That's exactly what I'm doing.  My command is called 
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 > > "tl-indent-region" (ok, we can drop the tl- prefix) and it relies
 > > on indent-rigidly to do the job.
 > 
 > Great.  Sounds good.  I misunderstood that you wanted to change
 > `indent-rigidly'; sorry.
 > 
 > > My command behaves the same as indent-rigidly when called with
 > > a numeric prefix argument.
 > 
 > Yes, that I understood from the code.

Changing the key binding but not the command itself, as you said you
were doing, would be fine.  There is no reason to change
`indent-rigidly' itself.

"My command" should have remained just that: a separate command.
The fact that without a prefix arg it behaves the same as
`indent-rigidly' is irrelevant, except as a (weak) argument for
someone wanting to replace `indent-rigidly'.  It means nothing for
someone truly intending to add a new command and bind it by default
to `C-x TAB'.

What is important is to keep two separate functions, and not screw
`indent-rigidly'.

This portion of the thread is also relevant, as it seems to be what has
now been implemented, in spite of the discussion:

d> A mix would also be possible, but less desirable IMO: modify
d> `indent-rigidly' to provide the new behavior only interactively,
d> never when used in code.  That has the disadvantage of not letting
                                                          ^^^^^^^^^^^
d> code take advantage of the indentation-to-tab-stop behavior.
d> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
d> I think it best to provide a separate command.
d> 
d> A separate command also lets any user who prefers the current default
d> behavior interactively to bind `indent-rigidly', instead of your
d> command, to `C-x TAB'.  You find it handy to indent to a tab stop by
d> default (ARG = nil), and then repeat (e.g., C-x z z z z).  Someone
d> else might find it handier to indent one column instead of one tab
d>                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
d> stop by default, and then repeat to indent the region incrementally.
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The simplest approach is the best one, for these and other reasons
discussed: Provide the new command.  Even make it the new default
binding for `C-x TAB'.  But keep `indent-rigidly' as it has been.
Simple, sane, no downside, wise.