bug#38354: 27.0.50; Implement display action display-buffer-in-tab

[martin rudalics]

>> If so, then we should decide whether we always want to stick to that
>> limitation or, eventually allow moving tabs between frames, probably
>> using window states for that purpose.  And we have to decide whether
>> such moving of a tab would mean making a completely self-reliant copy
>> of it or keep properties of it shared among frames.  And eventually we
>> should decide whether tabs could become first-class citizens - have a
>> life of their own without being attached to any frame.
>
> There are two separate cases to consider:
>
> 1. Moving an inactive tab to another frame.
>     In this case we need to use its window-state, not window-configuration,
>     i.e. just delete the window-configuration from tab data, then it
>     could be moved to another frame without problems.
>
> 2. Moving the current tab to another frame.  Here we need to save
>     window-configuration of another frame to its inactive tab, then clone
>     the original frame to another frame.  Do you know if such a function
>     already exists that duplicates all frame parameters with frame-root
>     window-state to another frame?

With "moving" I really meant "copying" or "cloning" with the
additional possibility of deleting the original.  So there should be
only one question: Can we simply make a copy of a tab using its window
state (window configurations can't be used because we cannot clone
windows).  If not, what is the problem?

> An additional question to consider is how to interactively select
> an another frame: by frame name, or using other-frame with a numeric
> prefix argument?

How is this question related to tabs?

>>> (push '("test1" .
>>>           ((display-buffer-reuse-window display-buffer-in-tab)
>>>            (reusable-frames  . visible)
>>>            (name . "Tab1")))
>>>         display-buffer-alist)
>>
>> What would be the downside of it?  The 'reusable-frames' would specify
>> the list of frames to investigate - the other dimension you mentioned
>> above.
>
> We need an alist entry that will tell display-buffer-reuse-window
> to search in tabs.  Maybe just the presence of the 'use-tabs' param
> will tell display-buffer-reuse-window to search in tabs like:
>
> (push '("test1" .
>           (display-buffer-reuse-window
>            (reusable-frames  . visible)
>            (use-tabs . t)))
>         display-buffer-alist)

There is one thing I apparently do not understand yet: When you enable
'tab-bar-mode' it is global - that is any window ever shown on any frame
is also in at least one of that frame's tabs.  Is that right?  So what
would 'use-tabs' mean here when every window is in a tab already?

>>    By default, a new tab starts with the current buffer that was current
>>    before calling the command that adds a new tab.
>>
>> That's confusing, at least.
>
> Maybe this is better?
>
>    By default, a new tab starts with the buffer that was current
>    before calling the command that adds a new tab.

The current buffer is IMHO a much too obscure object to consider here.
Don't you mean the buffer of the selected window?

martin