bug#19267: 25.0.50; Enhance cycle-spacing with a state where only whitespace after point is deleted

[Lars Ingebrigtsen]

Tassilo Horn <tsdh@gnu.org> writes:

>> I think that sounds like a good feature -- we don't have any other
>> commands for "delete all whitespace after point", do we?
>
> No, just the opposite: delete-horizontal-space with prefix arg.

Huh, I'd forgotten about that one.  It's pretty odd to have both `C-\'
and `M-SPC' bound when both commands are so similar.

I guess people have different usage patterns -- for instance, I only use
`M-- M-SPC' (`just-one-space' that also deletes newlines), because
that's what's usually useful in Lisp code.

>> We could implement this as a new third state for `cycle-spacing', and
>> move the "restore" to the fourth state.  Does anybody think that will
>> be annoying for people?
>
> It makes the sequence longer in case you want to restore.  Not a big
> thing IMHO.  But maybe there could also be a new defcustom
> cycle-spacing-actions which lists the actions being cycled, e.g.,
>
>   (just-one-space delete-all-space delete-space-after restore-original)

Hm, yes, that might be good.  If the list of cycled actions gets to
long, it's no longer convenient.  So for myself, I'd probably have

(just-one-space-including-newlines delete-after-space restore-original)

and then `M-SPC' would do what I wanted in 99% of the time (with my
usage patterns).  (We could also add target actions like `no-space' and
`no-space-before-point' (i.e., the `M-\' actions).)

So perhaps we could change the `M-SPC' binding to a new
`cycle-spacing-command' that, by default, does exactly what
`just-one-space' does now (so that there will be no user visible
changes; i.e., it doesn't cycle because cycle-spacing-actions will be
just (just-one-space)).  But then users can customize it and add the
actions they want in a convenient way.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no