Re: BUG: vared in function

["Bart Schaefer" <schaefer@candle.brasslantern.com>]

On May 31,  5:00pm, Bart Schaefer wrote:
} Subject: Re: BUG: vared in function
}
} On May 31, 11:28pm, Peter Stephenson wrote:
} > Subject: Re: BUG: vared in function
} > Peter Stephenson wrote:
} > > Bernd Eggink wrote:
} > > > Argh... 
} > > > 
} > > >    # t
} > > >    vared -cp "Aha: " BLAH
} > > > 
} > > >    % t
} > > >    t:vared:2: ZLE not enabled
} > > > 
} > > > This breaks lots of my scripts! 
} 
} This is happening because of my bug report to the effect that vared was
} improperly munging the TTY settings in an interactive shell that had ZLE
} explicitly turned off (as e.g. inside and emacs shell buffer).
} 
} I don't know how that interacts with Peter's patch (I'll try it later when
} I get home).

I should have been able to tell by looking closely at the patch, but this
re-breaks things when interactive in an emacs buffer without doing anything
new and useful for vared when not interactive.

In addition to the bug I previously mentioned:

} If you're going to pull this stuff out into a function, you need three
} return states, not two.

There's also a potential too-early return from bin_vared() a few lines
after the call to openttyspecially(), where `if (zleactive)' is tested,
and several more below that.  Can't just move the place where the tty
gets opened like that.

Peter had asked:

} > I don't think there's any good reason why zle shouldn't be enabled
} > especially.
} 
} In fact, what about this?  If it works for read, shouldn't it work for
} vared?

The difference is that `read' tests specifically for emacs-ness and does
not play with the tty settings in that case.  Running `vared' inside an
emacs buffer is the moral equivalent of running `vi' in one; it simply
can't work at all when it can't drive the editing itself.

You could ALMOST make `vared -c' work, but for any variable that already
has a value emacs is going to treat the old value as part of the prompt.

Given all of this, let's NOT use 11698, and instead use this:

Index: Src/Zle/zle_main.c
===================================================================
@@ -743,7 +743,7 @@
     char *p1 = NULL, *p2 = NULL;
     FILE *oshout = NULL;
 
-    if (unset(USEZLE)) {
+    if ((interact && unset(USEZLE)) || !strcmp(term, "emacs")) {
 	zwarnnam(name, "ZLE not enabled", NULL, 0);
 	return 1;
     }

Even this is not totally satisfactory, because modern versions of emacs
export TERM=dumb and EMACS=t rather than TERM=emacs.  However, TERM=emacs
is the canonical way to tell zsh it's in an emacs buffer, so I've had this
in my .zshrc for a while now:

case ${TERM:-dumb} in
emacs|dumb)
    [[ $EMACS = t ]] || return 0
    TERM=emacs
    export EDITOR=emacs
    stty -onlcr -echo
    ttyctl -f			# Doesn't really do any good
    ;;
eterm)
    TERM=vt100
    ;;
esac

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com

Zsh: http://www.zsh.org | PHPerl Project: http://phperl.sourceforge.net