bug#631: the M- notation suggestion

[xah lee <xah@xahlee.org>]

This is a suggestion on emacs's usability.

Recently in discussion at gnu.emacs.help, the subject of Alt+‹key›  
vs M-‹key› came up.

I think emacs's M-‹key› notation is one of emacs's a usability  
problem, contributing to its often cited big leaning curve.

Here's some detailed argument on why i think this should be chaged.  
Many emacs old users probably don't agree, but i thought it's good to  
send in one opinion anyhow.

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Emacs's M-‹key› Notation vs Alt+‹key› Notation

Xah Lee, 2008-07

Here're some reason i think emacs should adopt the Alt+‹key› and  
Ctrl+‹key› notation throughout its documentation. (as opposed to  
emacs's M-‹key› and C-‹key› notation)

UNIVERSALLY UNDERSTOOD

The Alt+‹key› or Ctrl+‹key› notation is universal among  
Windows and Linux. They account for about 95% of computers used word  
wide. Note that the word “Alt” and “Ctrl” are the exact labels  
printed on the Keys of PC Keyboards. PC Keyboards has probably more  
than 99% of market share.

IDENTICAL TO KEY'S LABEL

Using a notation that contains the actual label on keyboard's keys is  
much easier to understand. A beginning computer user, can read the  
“Ctrl+‹key›” notation and figure out which keys to press.  
Emacs's notation of “M-‹key›” and “C-‹key›” requires a  
learning step, even for experienced programers. Even though it is a  
minor one, but learning steps add up the complexity.

(Apple's computers, which account for about %4 marke share today,  
also use a notation where the name or symbol appears on the labels of  
Apple keyboard's keys exactly. (OSX's documentation uses the notaton  
“Command-‹key›” and “Option-‹key›”. Application's  
menus shows them as “⌘‹key›” and “⌥‹key›”. Both  
the word “Command” and symbol “⌘” appear on the key's label,  
same for “Option” and “⌥”.)
Meta Is Alt In Practice

By default on all major OSes in use (Windows and Linux and OSX),  
emacs maps its Meta to Alt key. So, practically speaking, the Meta  
key is the Alt key. (Aquamacs, perhaps the most widely used emacs  
distro on OSX, by default has Alt for Meta.)

KEYBOARDS DON'T HAVE META KEY TODAY

The Meta key was one of the modifier key on obsolete keyboards used  
by lisp machines in the 1980s. (for photos and detail, see: Why  
Emacs's Keyboard Shortcuts Are Painful)

There is practically no keyboard today that has the Meta key. Sun  
Microsystem's keyboard has a key labeled with a diamond “◆”.  
Sun's official documentation refers to this key as Meta key. (e.g.  
search http://docs.sun.com/ on “Meta key”.) Sun's keyboards have a  
market share perhaps less than 0.01%.

For photos and more commentary on Sun's keyboard, see Computer  
keyboards Gallery.

MISC FACTS

Historically, a “Meta+‹key›” shortcut in emacs can also be  
invoked by “Esc ‹key›” or “Ctrl+[ ‹key›”. The design  
was that way mostly because at the time, many terminals do not have  
or support the Meta key, and Terminal is a primary application in  
computer use in the 1980s. The other reason is that, in emacs's  
implementation, the Meta+‹key› is simply a ASCII control character  
sequence. Today, perhaps all terminal↗, console↗, Command line  
interface↗ apps support Meta as Alt either by default or in a  
preference setting.

The ability of pressing Esc for Meta might be still useful for some  
people. Users who needed that feature could easily read about it in  
emacs doc. (I myself used “Esc ‹key›” exclusively during  
1998-2004, mostly because it was a one-brainless solution that works  
on all telnet apps regardless of hardware, OS, or setup, and i  
frequently need to use different machine, OS, or remote servers.)

A argument from user interface perspective, is that multiple  
insignificant choices or options are not good because it increases  
complexity and causes the user to sidetrack their focus on tasks. KDE  
and Gnome, solved this problem for linuxes by adopting wholesale  
Microsoft Window's interface starting about 1998. (before KDE and  
Gnome, GUI apps on unix use a variety of “Windows Managers” that  
has incompatible User Interfaces, each claiming superiority.)

Note: Whether to use the “M-‹key›” or “Alt+‹key›”  
notation has little to do with “Esc ‹key›” feature.

PS Note that Microsoft Windows used to use the Alt-‹key› notation.  
Only in recent years they changed the minus sign to plus sign.  
Arguably, this is a good change because the plus sign better  
indicates key combination.

   Xah
∑ http://xahlee.org/

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