[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: Help!

Carl Fink wrote:
> Steve Lamb wrote:
> > I know that GNU lost me when it came to help systems when they
> > thought it was a keen idea to bind ^? and ^H to "help" in EMACS.
> > Sounds logical on paper until one realizes that ^? and ^H are
> > DEL/BS or BS/DEL depending on one's terminal settings.  So imagine
> > my first experience with EMACS where I was hitting backspace to
> > get rid of some text and kept getting popped into the help system.
> Ever talk to rms?  I guarantee his reaction would be something like "So
> change the keymappings, if you don't like them.  We give the user all the
> power."

Actually he firmly would insist that your terminal should produce DEL
and that any terminal that produces BACKSPACE should be corrected.

For historical reference IBM terminals send BS while others used DEL.
In the emacs PROBLEMS file:

  * Your Delete key sends a Backspace to the terminal, using an AIXterm.

  The solution is to include in your .Xdefaults the lines:

     *aixterm.Translations: #override <Key>BackSpace: string(0x7f)
     aixterm*ttyModes: erase ^?

  This makes your Backspace key send DEL (ASCII 127).

  * You type Control-H (Backspace) expecting to delete characters.

  Put `stty dec' in your .login file and your problems will disappear
  after a day or two.

  The choice of Backspace for erasure was based on confusion, caused by
  the fact that backspacing causes erasure (later, when you type another
  character) on most display terminals.  But it is a mistake.  Deletion
  of text is not the same thing as backspacing followed by failure to
  overprint.  I do not wish to propagate this confusion by conforming
  to it.

  For this reason, I believe `stty dec' is the right mode to use,
  and I have designed Emacs to go with that.  If there were a thousand
  other control characters, I would define Control-h to delete as well;
  but there are not very many other control characters, and I think
  that providing the most mnemonic possible Help character is more
  important than adapting to people who don't use `stty dec'.

  If you are obstinate about confusing buggy overprinting with deletion,
  you can redefine Backspace in your .emacs file:
    (global-set-key "\b" 'delete-backward-char)
  You can probably access  help-command  via f1.

And because the keyboard driver in the linux kernel also uses DEL
instead of BS then I think that convention will eventually win.


Attachment: signature.asc
Description: Digital signature

Reply to: