Re: Documentation of tab-bar-show and friends

[Juri Linkov]

>> >   *** The tab bar is frame-local when 'tab-bar-show' is a number.
>> >   Show/hide the tab bar independently for each frame, according to the
>> >   value of 'tab-bar-show'.
>> >
>> > What does it mean "frame-local" in this case?  Does it mean one should
>> > use a frame parameter called tab-bar-show?  Or does it mean something
>> > else?
>>
>> This means it affects each frame separately.
>
> How does it do that?  It's a good-faith question: I don't understand
> how you make that happen, except by using frame parameters.

Indeed, 'toggle-frame-tab-bar' modifies two frame parameters:
'tab-bar-lines' and 'tab-bar-lines-keep-state'.

>> > Next, the above says "a number", but the doc string of tab-bar-show,
>> > the defcustom forms, and the manual only describe one value: 1.
>> > However, the code does:
>> >
>> >    ((natnump tab-bar-show)
>> >     (if (> (length (funcall tab-bar-tabs-function frame)) tab-bar-show) 1 
>> > 0))))
>> >
>> > So tab-bar-show can be meaningfully set to a number other than 1.
>> > This is undocumented, for some reason.  Is that intentional?
>>
>> Probably no one would want to use a number other than 1.
>
> I don't think it's reasonable to second guess what the users would
> like doing.

Exactly, so this is the reason why there is no restriction
on possible future extensions that can support numbers greater than 1.