Re: Rename "window" to "pane" (after Emacs 27)

[Stefan Monnier]

> And would we then rename "frame" to "window", which

We won't be able to do that before (almost) all legacy uses of "window"
are gone (and not just from Emacs's own code), which will take many many
years (to get an idea: lexical-scoping and cl-lib are 7 years old now
and adapting code to them is much less intrusive than renaming all
`window`s to `pane`s), so it's important to realize that if it ever
happens we'll probably be significantly older than we are now.

W.r.t using "panes", we could start by making a *forward compatibility*
library `pane.el` distributed via GNU ELPA containing aliases to
the current `window` functions and variables.  Over time it can be
refined/improved to also rewrite docstrings and maybe try to tackle more
delicate issues (e.g. "alias" the `pane` property of overlays to
the `window` property).

This can be done without convincing anyone that we should rename
"window" to "pane", but can help prepare for it.


        Stefan