bug#70157: 29.3; Bad mouseover help for mode-line `d'

bug#70157: 29.3; Bad mouseover help for mode-line `d'

[Drew Adams via Bug reports for GNU Emacs, the Swiss army knife of text editors]

The default mouseover help text when editing a buffer in emacs-lisp-mode
is this:

  "Using old dynamic scoping mode"

That's incorrect and misleading.

1. There's no "NEW dynamic scoping mode".
2. Lexical binding is not new - it's as old as the hills.
   Even for Emacs it's not new - it's been available for quite a while.
3. There's technically no such thing as "dynamic scope" - that's a
   convenient misnomer.  The Common Lisp doc makes this clear:

   "In addition to the above terms, it is convenient to define dynamic
   scope to mean indefinite scope and dynamic extent.  Thus we speak of
   `special' variables as having dynamic scope, or being dynamically
   scoped, because they have indefinite scope and dynamic extent: a
   special variable can be referred to anywhere as long as its binding
   is currently in effect.

   The term `dynamic scope' is a misnomer.  Nevertheless it is both
   traditional and useful."
   https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node43.html#SECTION00700000000000000000

Emacs Lisp's approach to lexical and dynamic binding is very close to
that of Common Lisp, and it will become even closer (essentially the
same) when lexical binding becomes the default.

Emacs Lisp is not Scheme.  Dynamic binding is important to Emacs.  RMS's
arguments about this make perfect sense today, as they did decades ago:

http://www.gnu.org/software/emacs/emacs-paper.html#SEC17.

What the `d' help should say is that dynamic binding is currently the
default in the buffer.  Nothing more, nothing less.  Just the facts,
ma'am.

In GNU Emacs 29.3 (build 2, x86_64-w64-mingw32) of 2024-03-24 built on
 AVALON
Windowing system distributor 'Microsoft Corp.', version 10.0.19045
System Description: Microsoft Windows 10 Pro (v10.0.2009.19045.4170)

Configured using:
 'configure --with-modules --without-dbus --with-native-compilation=aot
 --without-compress-install --with-sqlite3 --with-tree-sitter
 CFLAGS=-O2'

bug#70157: 29.3; Bad mouseover help for mode-line `d'

[Eli Zaretskii]

tags 70157 notabug wontfix
thanks

> Date: Wed, 3 Apr 2024 03:34:48 +0000
> From:  Drew Adams via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> The default mouseover help text when editing a buffer in emacs-lisp-mode
> is this:
> 
>   "Using old dynamic scoping mode"
> 
> That's incorrect and misleading.

I disagree.  I see no reason to change what we have, and so I'm
closing this non-bug.