Re: bind does not modify key bindings

[Chet Ramey]

lyongu@gs3091.sp.cs.cmu.edu wrote:
> Configuration Information [Automatically generated, do not change]:
> Machine: i686
> OS: linux-gnu
> Compiler: /usr/local/bin/gcc
> Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i686' 
> -DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i686-pc-linux-gnu' 
> -DCONF_VENDOR='pc' -DLOCALEDIR='/usr1/local/bash/share/locale' 
> -DPACKAGE='bash' -DSHELL -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib   
> -I/usr/local/include -L/usr/local/lib -g -O2
> uname output: Linux gs3091.sp.cs.cmu.edu 2.4.25-001-P4+4GB+SMP #1 SMP Fri Mar 
> 26 22:57:11 EST 2004 i686 i686 i386 GNU/Linux
> Machine Type: i686-pc-linux-gnu
> 
> Bash Version: 3.1
> Patch Level: 7
> Release Status: release
> 
> Description:
>       `bind` does not modify key bindings.
> 
> Repeat-By:
>         $ bind -r '\M-p'
>         $ bind '"\M-p":history-search-backward'

It does, actually.  Bash-3.1 key bindings interpret the "\M-" prefix the
same way that the dispatch code does:  if the convert-meta flag has been
set, the sequence is converted into an escape-prefixed sequence and
bound accordingly.  If that variable is off, the eighth bit is turned
on (`metafying' the following character).

What bash-3.1/readline-5.1 did not do (and has been changed since) is
change the code that bind -p calls to list key bindings to not use
the \M- prefix for escape-prefixed key sequences when convert-meta is
off.

The following sequence of commands should illustrate the difference.
The cat -v is in there to make the M-p visible.

caleb.ins.cwru.edu(2)$ echo $BASH_VERSION
3.1.7(3)-release
caleb.ins.cwru.edu(2)$ bind 'set convert-meta off'
caleb.ins.cwru.edu(2)$ bind -p | cat -v | grep 'M-p'
"\M-p": non-incremental-reverse-search-history
"M-p": self-insert
caleb.ins.cwru.edu(2)$ bind -r '\M-p'
caleb.ins.cwru.edu(2)$ bind -p | cat -v | grep 'M-p'
"\M-p": non-incremental-reverse-search-history
caleb.ins.cwru.edu(2)$ bind '"\M-p":history-search-backward'
caleb.ins.cwru.edu(2)$ bind -p | cat -v | grep 'M-p'
"M-p": history-search-backward
"\M-p": non-incremental-reverse-search-history
caleb.ins.cwru.edu(2)$ bind 'set convert-meta on'
caleb.ins.cwru.edu(2)$ bind -p | cat -v | grep 'M-p'
"M-p": history-search-backward
"\M-p": non-incremental-reverse-search-history
caleb.ins.cwru.edu(2)$ bind -r '\M-p'
caleb.ins.cwru.edu(2)$ bind -p | cat -v | grep 'M-p'
"M-p": history-search-backward
caleb.ins.cwru.edu(2)$ bind '"\M-p":history-search-backward'
caleb.ins.cwru.edu(2)$ bind -p | cat -v | grep 'M-p'
"\M-p": history-search-backward
"M-p": history-search-backward


This should be cleaner in the next release.

Chet

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
( ``Discere est Dolere'' -- chet )
                                           Live Strong.  No day but today.
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/