Help customising the behaviour of the new Tab Line mode

[R. Diez]

Hi all:

I have been accumulating frustration with Emacs since many years, but the 27.1 
release got me excited again. Specifically:


Feature 1) "Mouse scroll up and down with control key modifier changes font 
size."

Wow, zoom in, like everybody else!


Feature 2) Tab Line mode

Tabs! Official tabs!!! Finally!!!!!

Could it be that the Emacs developers are actually listening to us, humble 
users????


I have already written in this mailing list about how important tabs are for me, because they help me use my positional memory to switch 
quickly between documents. The gory details are here:

https://lists.gnu.org/archive/html/help-gnu-emacs/2018-06/msg00289.html

For example, I tend to have source.h to the left and source.cpp to the right, so that I can quickly switch between them. I tend to keep all 
such .h & .cpp files in pairs on the tab bar. I know I could use 'ff-find-other-file' for that, but I use these positional navigation in 
many other situations, like base.h to the left, and derived.h to the right. And so on.

I have been using old package tabbar.el, but it is full of bugs and quirks. There are some variants with other bugs and quirks. I have 
compensated with my poor Lisp. But now, I want to do it "right" with the new Tab Line mode in Emacs 27.1.


Issue 1) The first thing I noticed is that 'compile' creates a window/pane/whatever for the compilation output, and the tab line at the top 
does not show the compilation buffert. In fact, if I call split-window-below, the tab line below only has the current buffer on it. However, 
I would like all Tab Lines to show all buffers (or at least all buffers visited in the whole frame). And I want all those buffers to have 
the same tab order (because my positional memory is useful, but limited). That would match the behaviour of the old tabbar.el package. How 
do I achieve that? Please remember that my Lisp is rather limited. I can tinker, but it won't be pretty. 8-)


Issue 2) The second thing I am missing is the ability to reorder tabs. I actually do not touch the mouse for that. To get an idea of what I 
am looking for, open a few web pages in Firefox or Chromium, and then:

- Press Ctrl+PageUp to move the current view a few pages to the right.
- Press Ctrl+Shift+PageDown to move the current tab to the left, exchanging its 
position with the previous tab.

With key shortcuts Ctrl+Shift+PageUp and Ctrl+Shift+PageDown, I have got used to reordering tabs very quickly. It is like reordering your 
objects on your physical desktop to your liking, so that you always find everything quickly.

Has anybody written some Lisp to achieve that reordering with Emacs 27.1's Tab 
Line mode?


Many thanks in advance,
  rdiez