Aucb.126
fa.editor-p
utzoo!decvax!ucbvax!C70:editor-p
Tue Dec 8 13:21:34 1981
Number of keystrokes in Control-Meta-D
>From Guy.Steele@CMU-10A Tue Dec 8 13:18:54 1981
I would also agree that, on an ASCII keyboard, Control-Meta-D is
closer to three keystrokes, at least physically, than to one.
Conceptually, I think I think of it as two keystrokes.
But I would like to lay emphasis on a point that was brought up
earlier in this discussion: EMACS was originally designed for
special keyboards with orthogonal Control and Meta keys; this is
how the terminology originally arose. Little or no thought was
given in the original command layout to keystroke efficiency on
ASCII keyboards. I can assert this because I originally collated
the first primitive and rudimentary EMACS command set, drawing
on the work of many others on pre-EMACS but EMACS-like extensions
to ITS TECO. Since then the command set has been extensively
refined and polished, with more attention given to ASCII keyboards,
and nearly all of the credit for this belongs to Richard Stallman
(as well as credit for nearly all of the original implementation
effort).
Attention was given, however, to keystroke efficiency on these
special keyboards. It was for this, as well as menmonic reasons,
that commands were grouped the way they were. This is particularly
true of the word commands, and a bit less true of the LISP commands.
While "delete word" is two keystrokes (hit meta key, hit D),
"delete three words" is only four keystrokes (meta, D, D, D).
This is also why certain commands behave in what might otherwise seem
odd or inconsistent ways. One case in point is the transpose commands,
which transpose two two objects surrounding the cursor, but also
*move the cursor*, thus: FOO/\ BAR ==transpose word==> BAR FOO/\.
The reason for this odd motion of the cursor is because (we think)
one wants to undo a transposition less often than to move a word
several positions. By leaning on the meta key and hitting T several
times one can move a word several places.
Similarly, consider the word uppercase, lowercase, and capitalize
commands. These move over the affected word so that one can lean on
the meta key and convert several words with fewer keystrokes. While
on an ASCII keyboard converting
the feynman lectures on physics, volume ii
to
The Feynman Lectures on Physics, Volume II
takes fourteen keystrokes (ESC C ESC C ESC C ESC L ESC C ESC C ESC U),
on the special keyboard it takes only eight (Meta C C C L C C U).
Now other editors have a special "do that again" command, or several
varieties (such as repeat last cursor motion, repeat last deletion,
etc.). However, I believe it takes a bit more time to shift to that
key than to just hit the same key several times (this is an unsubstantiated
conjecture, of course).
--Guy
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