Text editors: data vs commands and optimal keyboard layout

[moon_aka_sun]

Only 37% of key strokes involve data entry (text), while the rest 63% are commands.

Emacs's Command Frequency
An Ergonomic Keyboard Shortcut Layout For Emacs
Emacs's Keybinding Layout
Emacs Lisp Function Frequency

An Ergonomic Keybinding Design For Emacs

Xah Lee, 2007-07

Emacs's default keybindings are very ergonomically painful, for
several reasons. (For detail, see: Why Emacs's Keyboard Shortcuts Are
Painful.)

For a visual layout of emacs's default keybindings, see: Emacs's
(default) Keybinding Layout.

This page shows a redesign of emacs's shortcut set, based on ergonomic
principles. Here's the outline of how this design is arrived:

All the commands that has a default shortcut of M- and C- are listed.
This command set is then ordered by their frequency of use. Then,
commands with higher frequency of use are mapped to the most easy-to-
press keys. Specifically: Meta combinations is easier than Control,
home keys are easier than non-home keys, and keys pressed by the index
and middle fingers are better than keys pressed by the ring finger and
little finger. (this design principle is similar to the design
priciple of Dvorak keyboard layout↗.

Secondarily, similar commands are placed together. For example,
forward-char, backward-char, previous-line, next-line (these are the
arrow key commands) are all mapped to the right hand's home position
in a inverted T layout. Copy/cut/paste are all ajacent to each other.
By placing similar commands together, the keyboard shortcuts are made
easier to remember. If we strictly go by command frequency with ease-
of-key-press, then similar commands will be scattered all over. By
placing similar commands together, the logical positioning makes it
more coherent and easier to use, with no decrease in speed of
execution. (because keyboard shortcuts are not like typing. Each
shortcut is called only every few minutes)

Of Emacs's shortcut set, the most frequently used commands can be
grouped into 3 categories: (1) Those move the cursor. (2) those
manipulate text. (3) Other. Cursor moving commands include moving the
cursor to beginning/ending of char/word/line/sentence/paragraph/
screenful/file. Text editing commands includes copy/cut/paste, paste
previous (yank-pop), kill-line, and some others such as fill-
paragraph, just-one-space, comment-dwim. Also, commands such as mark-
paragraph, are considered in this group. The third group, are commands
such as execute-extended-command (M-x), keyboard-quit (C-g), and few
others.

(For a statistics of command frequency, see Emacs Commands Frequency.)

In the Dvorak layout design, all vows are placed on the left hand's
home row, and the most frequently used consonants are placed on the
right hand's home row. The idea is that hands will alternate. We
borrow this idea, by placing all cursor movement commands under the
right hand, and all text editing commands (such as copy/cut/paste/kill-
line) under the left hand.
Ergonomic Emacs Keybinding Layout

The following shows a layout of the redesign.

In this design, only the M-«key» shortcuts are redefined. (and with
some Meta-shift definition as well). Shortcuts involving Control key,
or any other key sequence, are untouched. This is so to avoid radical
change that will require a lot coding efforts on every major/minor
mode's keymaps. Emacs's default shortcut does not put much weight on
commands using the Meta-«key» space. By using the single-key shortcut
space of M-«key», the operation and consistency of emacs's shortcuts
are practically uneffected, while 95% of command calls now have home-
row keystrokes with the thumb down.

This design, since it is based on finger positions and not on command
name's first letters, it is the same on QWERTY and Dvorak keyboard
layout.

This colored commands means holding down the Meta/Alt key. This
colored commands means holding down both Meta and Shift. A blank key
means it is unaltered from emacs's default command keybinding for that
key.

For clarity, some command names are replaced with glyphs. Here's what
they mean:
LEGENDS

←   ackward-char
→   orward-char
↑    previous-line
↓    next-line

←w   backward-word
→w   forward-word
←s   backward-sentence
→s   forward-sentence
↑¶    backward-paragraph
↓¶    forward-paragraph


|←   move-beginning-of-line
→|   move-end-of-line

▲    scroll-down (page up)
▼    scroll-up (page down)
◀    beginning-of-buffer
▶    end-of-buffer


⌦    delete-char
⌫    delete-backward-char
⌦w   kill-word
⌫w   backward-kill-word
⌦l   kill-line
⌦s   kill-sentence

copy      kill-ring-save
✂        kill-region (cut)
paste     yank
paste     yank-pop
previous

M-x       execute-extended-command

Shown with QWERTY

[QWERTY keyboard layout in HTML table]

[Dvorak keyboard layout in HTML table]


Emacs Lisp Code for Rebinding

Here's the emacs lisp file for the above ergonomic keybinding design.
ergonomic_keybinding_dvorak.el and ergonomic_keybinding_qwerty.el.
Please send your comments or suggestions.

Displaced Commands

The following table shows commands that are displaced by this
rebinding. Those with a asterisk * means they no longer have a
shortcut. You will need to bind them if you need them:

Displaced Commands QWERTY Dvorak

[HTML table]

Un-remapped Frequently Used Commands

One of the top most used command is isearch-forward and isearch-repeat-
forward. Together, they are called 1.14% with respect to all commands
calls. “isearch-forward” should have a keyboard shortcut probably as M-
s in this design. However, to redefine keymaps for isearch-forward
involves non-trivial elisp coding by redefining its keymap. This is
currently not done.

There are several other commands that are frequently used and could be
incorporated into this shortcut design. To be conservative, they are
currently left out from this keybinding remap. These are listed below,
with parenthesis showing their default shortcuts:

Common commands in modern applications that emacs do not have
equivalent or have difficult to press shortcuts: save-buffer (C-x C-
s), write-file (save as; C-x C-w), «kill-buffer-quitely» (close tab/
window; C-x k), «next-user-buffer» (next tab/window), «previous-user-
buffer», mark-whole-buffer (select all; C-x h).

Frequently used emacs commands that could use easier M- shortcuts:
keyboard-quit (cancel; C-g), dired (C-x d), list-buffers (C-x C-b; or
ibuffer), quoted-insert (C-q).

Frequently used emacs commands that does text transformations. Some of
these's default shortcut keybindings are taken by ergonomic redesign
(on Dvorak or QWERTY): mark-paragraph (M-h), downcase-word (M-l),
upcase-word (M-u), abbrev-prefix-mark (M-'), dabbrev-expand (M-/),
fill-paragraph (M-q), «remove-hard-wrap-paragraph», just-one-space (M-
SPC), delete-blank-lines (C-x C-o), comment-dwim (M-;).

Those in «angle brackets» indicate custom functions common to most
modern text editors but does not exist in emacs. Here are some
explanation of them:

• kill-buffer-quitely should be like kill-buffer. It will kill the
current buffer without prompting if the buffer is not unsaved. This is
similar to close window (Alt+F4, Cmd-w) or close current tab in modern
applications.

• next-user-buffer (and previous-user-buffer) switchs to the next
buffer among user's files. (i.e. skipping emacs internal buffers or
those not having to do with normal files. e.g. *scratch*, *Messages*,
*shell*.) This is similar to next tab or next window in modern
applications.

• remove-hard-wrap-paragraph does the reverse of fill-paragraph.
Namely, remove the line endings of the paragraph the current cursor is
on.

For lisp code that does the above 3 functions, see
modern_operations.el.

----

  Xah
  xah@xahlee.org
∑ http://xahlee.org/

A surprise finding: Better Shortcut Layout vs Better Key Layout

On the subject of keyboarding ergonomics, a user may wonder whether
switching from QWERTY to Dvorak provides a better improvement than
switching from a lousy to better keyboard shortcut layout. (Assuming
that he does only one of the above.)

Of my Emacs Commands Frequency study, 37% of key strokes involves data
entry (that is, calling the commands “self-insert-command” and
“newline” (pressing return), while the rest 63% are calling all other
commands. This seems counter-intuitive, because one might think typing
should probably be the bulk of activity and moving cursor and deleting
text or other commands are only done few times per minute.

If we include commands invoked by the Backspace key as data entry,
then 40% are data entry, while 60% are editing commands. Still
surprising. Going one step further, if we consider the next group of
most used commands of moving the cursors by the smallest unit (i.e.
previous-line (C-p), next-line (C-n), backward-char (C-b), forward-
char (C-f) (also invoked by the physical arrow keys)) as part of data
entry, then, 64% are data entry and 36% are other command calls.

This data seems to indicate, that a better shortcut layout is as
important as a better key layout, at least for computer programing
related editing tasks done in emacs.

In anycase, if you are not using a Dvorak layout already, you probably
should consider switching to it.

Better Shortcut Layout vs Better Key Layout

On the subject of keyboarding ergonomics, a user may wonder whether
switching from QWERTY to Dvorak provides a better improvement than
switching from a better keyboard shortcut layout. (Assuming that he
does only one of the above.)

Of my Emacs Commands Frequency study, 37% of key strokes involves data
entry (that is, calling the commands “self-insert-command” and
“newline” (pressing return), while the rest 63% are calling all other
commands. This seems counter-intuitive, because one might think typing
should probably be the bulk of activity and moving cursor and deleting
text or other commands are only done few times per minute.

If we include commands invoked by the Backspace key as data entry,
then 40% are data entry, while 60% are editing commands. Still
surprising. Going one step further, if we consider the next group of
most used commands of moving the cursors by the smallest unit (i.e.
previous-line (C-p), next-line (C-n), backward-char (C-b), forward-
char (C-f) (also invoked by the physical arrow keys)) as part of data
entry, then, 64% are data entry and 36% are other command calls.

This data seems to indicate, that a better shortcut layout is as
important as a better key layout, at least for computer programing
related editing tasks done in emacs.

In anycase, if you are not using a Dvorak layout already, you probably
should consider switching to it.

http://xahlee.org/emacs/ergonomic_emacs_keybinding.html

  Xah
  xah@xahlee.org
∑ http://xahlee.org/

news:comp.emacs, Xah Lee, Jul..Sep 2007

Очень удивлюсь, если кому-то ещё это интересно.