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From: KFL@MC.LCS.MIT.EDU ("Keith F. Lynch")
Newsgroups: mod.computers.vax
Subject: XON XOFF and EMACS
Message-ID: <[MC.LCS.MIT.EDU].847605.860311.KFL>
Date: Tue, 11-Mar-86 21:01:54 EST
Article-I.D.: <[MC.LCS.MIT.EDU].847605.860311.KFL>
Posted: Tue Mar 11 21:01:54 1986
Date-Received: Thu, 13-Mar-86 00:09:34 EST
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    From: mcvax!delphi!mdc@seismo.CSS.GOV

    I think that a solution may be :
    Add to XON XOFF a quote character  QUOTE (for example ^P).
    So at the hardware level , 

    ^P    is a prefix character
    ^Q    means  stop sending data
    ^S    means  start sending data
    ^P^Q  means just the ascii character ^Q
    ^P^S  means just the ascii character ^S
    ^P^P  means just the ascii character ^P

  In Emacs, text characters always self-insert, and control characters
are always commands.  ^S is the search command and ^Q is the quote-next-
character command (allowing insertion of, and searching for, control
characters).  ^P is the 'up arrow' command, and ^N the 'down arrow'
command.  This is all very easy to use and intuitive, as should be
expected based on the fact that Emacs was in essence incementally
designed by hundreds of users all over the world over a period of over
ten years.  (There has long been a network mailing list for
suggestions and complaints, and another one for bug reports.)
  So to search for a ^S in a file, you do ^S^Q^S  (Search for a Quoted
control-S).  With your suggestion this simple command would turn into
^P^S^P^Q^P^S.  Note that there is two levels of quoting here, and with
different quote characters.  Many novice users have a hard time
mastering one.  And suppose someone wanted to create an Emacs macro
file, which would contain the command ^S^Q^S.  To key it in now
requires the user to do ^Q^S^Q^Q^Q^S.  With your suggestion it would
become ^P^Q^P^S^P^Q^P^Q^P^Q^P^S.  This is not reasonable.  Commands
are already confusing enough without adding new layers of protocol
that add no new features and make life more difficult.
  Also, while going down one line would remain ^N, going up one line
would become ^P^P.  But only interactively.  In a macro it would be a
single ^P.  But you would still have to type two to insert it.  In
addition to a ^Q to quote the ^P to Emacs and another ^P to quote the
^Q which quoted the ^P which was also quoted by another ^P.  What a
nightmare!
  And presumably this change would only take place on VAXes.  I can't
see maintainers of Emacs on other machines changing their Emacs to be
compatible with the changes necessitated on VAXes by losing DEC
protocols.
  In any case, I have used Emacs a great deal on VMS VAXes and have
had no problem with it, except on a DEC terminal in smooth scroll
mode.

    I agree, however, that XON XOFF is too widely used to 
    ignore it or to change it now ...

  EMACS is too widely used to ignore it or to change it now!

								...Keith