randy@mit-eddie.UUCP (03/04/87)
Does anyone have an idea how possible/easy it would be to define a
key as a prefix for control? In other words, to allow a two key
substitution for any control key? (Example: 'C-v s' substitutes for
'C-s'. C-v would be a bad choice, but you get the idea). Loosely, to
define an equivalent of the escape key for Control? I remember seeing
this in some earlier emacs (I think the original twenex version). The
manual describes the key bindings, but doesn't give any general method
to get at a key's corresponding control definition.
This strikes me as being an easy and general solution to the problem
of terminal servers etc. catching ^S and ^Q. Redefinition of C-^ and
C-\ relies on your terminal being able to produce them, and my home pc
(Macintosh) can't. Suggestions/questions/comments/flames?
-- Randy Smith
UsMail: Randy Smith Uucp: . . .!seismo!elsie!ncifcrf!randy
c/o PRI, Inc.
PO Box B, Bldng. 430
Frederick, MD 21701 matt@oddjob.UUCP (03/05/87)
I don't believe the addresses that seismo is sticking on, but...
randy@seismo.CSS.GOV@ncifcrf.UUCP (Randy Smith) writes:
) Does anyone have an idea how possible/easy it would be to define a
) key as a prefix for control? In other words, to allow a two key
) substitution for any control key? (Example: 'C-v s' substitutes for
) 'C-s'. C-v would be a bad choice, but you get the idea).
TVI terminals have a key "FUNCT" which, if held while typing
some other key x, sends C-A x C-M. I made this act as a meta
key by using:
(defun funct-key ()
"Make the TVI's FUNCT key act like a META key"
(interactive)
(let ((save-key (read-char)))
(if (/= (read-char) ?\^M)
(error "bad C-A or FUNCT key usage")
(setq prefix-arg current-prefix-arg
this-command last-command
unread-command-char (logior save-key 128)))))
(define-key global-map "\^A" 'funct-key)
Speaking off the top of my head, you have two main choices. You
can emulate and simplify the above to:
(defun prefix-control ()
"Make the net character act like the corresponing control character"
(interactive)
(setq prefix-arg current-prefix-arg
this-command last-command
unread-command-char (logand (read-char) 31)))))
;; A more sophisticated version would map ? to DEL
The other choice is to make a new keymap that does indirection
through whatever keymap is in effect. Binding a key sequence to
a string has this effect - it's essentially a keyboard macro.
(setq control-map (make-keymap))
(fset 'prefix-control control-map)
(setq i 0)
(while (< i 32)
(define-key control-map (char-to-string (+ i ?@)) (char-to-string i))
(define-key control-map (char-to-string (+ i ?`)) (char-to-string i))
(setq i (1+ i)))
(define-key control-map "?" "\^?")
(define-key global-map "\^V" 'prefix-control) ;or whatever key you want
In either case, the extension to "prefix-control-meta" is left
as an exercise for the reader.
Keep out of trouble, Randy.
Mattrbj@ICST-CMR.ARPA.UUCP (03/05/87)
> Speaking off the top of my head, you have two main choices. You > can emulate and simplify the above to: > > (defun prefix-control () > "Make the next character act like the corresponding control character" > (interactive) > (setq prefix-arg current-prefix-arg > this-command last-command > unread-command-char (logand (read-char) 31))))) > ;; A more sophisticated version would map ? to DEL Here's where you become more sophisticated. You have just illustrated one of my pet peeves: special casing `?' in control code functions. Why do you think DEL is `^?'? There is a function that will map both letters AND the apparant special case `?': char XOR 64. Of course, this forces you to type ^A instead of ^a, so it is more useful as an output transformation than as an input one: ^a maps to `!'! It is amazing how many people don't know this trick, so don't feel bad. > Matt (Root Boy) Jim "Just Say Yes" Cottrell <rbj@icst-cmr.arpa> I think I am an overnight sensation right now!!
earleh@dartvax.UUCP (Earle R. Horton) (03/06/87)
In article <8703042025.AA12061@ncifcrf.ncifcrf.uucp>, randy@seismo.CSS.GOV@ncifcrf.UUCP (Randy Smith) writes: > > > Does anyone have an idea how possible/easy it would be to define a > key as a prefix for control? ... > Redefinition of C-^ and > C-\ relies on your terminal being able to produce them, and my home pc > (Macintosh) can't. Suggestions/questions/comments/flames? > > -- Randy Smith Lest anyone get the idea that the Macintosh lacks the ability to generate control characters, or is an unsatisfactory substitute for a "real" terminal in any way, allow me to correct that impression. Mr. Smith suffers from one of two possible ailments, a) inferior terminal emulator, or b) forgot to read the user's manual. In order to avoid messing around with lisp code for hours, I would recommend that you throw out your present terminal emulator and get a) MacKermit, b) uw, or c) VersaTerm. The first two are free and allow generation of any character you can think of, even eight- bit jobs. VersaTerm provides the opportunity to spend money, but has more features, although the programmer seems to have neglected eight-bit characters. uw is nice for UNIX, since you can run a server on the host that services 7 (!) pseudo ttys in separate windows on the Macintosh. Also, if you have BSD 4.3, window size changes in uw are communicated to programs running on the host (!) Also, uw encodes ^S and ^Q into two-byte sequences, which are decoded by the server and passed to emacs or whatever as ^S or ^Q. This means that when running uw, nobody can touch my ^S or ^Q but emacs! MacKermit comes with a separate utility program that allows mapping of keys to anything: strange control characters, eight-bit characters, whole sentences, anything you want, and it emulates a vt102. uw emulates a vt52, Ann Arbor Ambassador (ANSI), adm31, or tek 4012. VersaTerm does VT100, VT52, and tek 4012 (4105 in the more expensive version). I would suggest this to Mr. Smith: throw away that terminal program you are using if it can't do ^^ and ^\, and get a real one! I realize that this article has very little to do with emacs, but I don't want people to go around thinking I can't generate all the ^\'s or ^^'s I want to with my Mac!