Completing strings from history?

Completing strings from history?

[John Cooper]

[ZSH_VERSION is 4.0.1-pre-2]

Typing `foo<ESC-/>' (bound to _history-complete-older) finds the most recent
word in the history beginning "foo".  Typing <ESC-/> again appears to do
nothing.

Is it possible to set things up so that repeatedly typing <ESC-/> cycles back
through all matches in the history?  (ala Emacs' dabbrev-expand)

Thanks,

    --- John

Re: Completing strings from history?

[Peter Stephenson]

> Typing `foo<ESC-/>' (bound to _history-complete-older) finds the most recent
> word in the history beginning "foo".  Typing <ESC-/> again appears to do
> nothing.
> 
> Is it possible to set things up so that repeatedly typing <ESC-/> cycles back
> through all matches in the history?  (ala Emacs' dabbrev-expand)

You can do this by setting the `stop' style, which is so called because it
stops when it has reached as far back into the history as it can (unlike
normal menu completion which would continue cycling).

  zstyle ':completion:history-words:*' stop 1

You should also be able to turn on menu completion just in this context,
but I couldn't get that to work with a brief try, for some reason.

What doesn't work which probably ought to is that if you type `\e,'
(_history-complete-newer) it should cycle back in the other direction.
Probably nobody thought about it at the time.

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Unit 300, Science Park, Milton Road,
Cambridge, CB4 0XL, UK                          Tel: +44 (0)1223 392070

Re: Completing strings from history?

[Adam Spiers]

Peter Stephenson (pws@csr.com) wrote:
> What doesn't work which probably ought to is that if you type `\e,'
> (_history-complete-newer) it should cycle back in the other direction.
> Probably nobody thought about it at the time.

Works for me with:

  zstyle ':completion:*:history-words' stop verbose

Re: Completing strings from history?

[John Cooper]

Peter Stephenson <pws@csr.com> writes:

 > > Typing `foo<ESC-/>' (bound to _history-complete-older) finds the most recent
 > > word in the history beginning "foo".  Typing <ESC-/> again appears to do
 > > nothing.
 > > 
 > > Is it possible to set things up so that repeatedly typing <ESC-/> cycles back
 > > through all matches in the history?  (ala Emacs' dabbrev-expand)
 > 
 > You can do this by setting the `stop' style, which is so called because it
 > stops when it has reached as far back into the history as it can (unlike
 > normal menu completion which would continue cycling).
 > 
 >   zstyle ':completion:history-words:*' stop 1

Ideally, I'd prefer <ESC-/> to cycle back through the history _and_ have it
cycle round after reaching the end of the history.  Is this possible?

With the above zstyle, I find that hitting <ESC-/> after having reached the
oldest history item prohibits <ESC-,> from taking my forwards again, and
similarly, hitting <ESC-,> after cycling forwards to the most recent item
prohibits <ESC-/> from taking me backwards again.

Two more questions:

1. Is it possible to turn off the beep that's emitted every time I type <ESC-/>?

2. Can all matching words be displayed as per normal completions (then I'd see
   whether it's worth continuing to bang on <ESC-/> a few more times)?

Thanks again,

    --- John

Re: Completing strings from history?

[Bart Schaefer]

On Mar 26,  2:34pm, Peter Stephenson wrote:
} Subject: Re: Completing strings from history?
}
} > Is it possible to set things up so that repeatedly typing <ESC-/>
} > cycles back through all matches in the history? (ala Emacs'
} > dabbrev-expand)
} 
} You can do this by setting the `stop' style, which is so called
} because it stops when it has reached as far back into the history as
} it can (unlike normal menu completion which would continue cycling).
} 
}   zstyle ':completion:history-words:*' stop 1

Hmm, this works, but it's a bit strange -- it beeps every time there's a
completion, and stops beeping when it has run out of completions (which
I think is because it believes it has found a unique match).

You can at least see what it's doing if you use:

    zstyle ':completion:history-words:*' stop verbose
 
} You should also be able to turn on menu completion just in this context,
} but I couldn't get that to work with a brief try, for some reason.

Turning on menu completion should have approximately the same effect as
the `stop' style.  (I'm not sure if that's intentional, or if the intent
was instead to cycle, but the function doesn't differentiate between the
`stop' style and menu completion.)

However, _history_complete_word tests for menu completion by examining
compstate[insert], not by examining a style, and _history_complete_word
is a widget wrapper around _main_complete, so the only way that you can
get compstate[insert] to be `menu' is to `setopt menucomplete' and also
to `unsetopt automenu' (I think).

Finally, the manual entry for the `stop' style is a little misleading:
If it's set to ANYTHING, you get stopping-menu behavior, with the extra
effect of `verbose' as described; setting the style to `false' or `0'
won't do what's implied.
 
} What doesn't work which probably ought to is that if you type `\e,'
} (_history-complete-newer) it should cycle back in the other direction.

The function attempts to do that, but it gets it wrong in the boundary
conditions; that is, if you've ever actually reached the beginning or the
end of the history, you lose the ability to reverse direction.  Maybe that
was intentional too (no point in showing you the entire history more than
once) but somehow I doubt it.

The following patch makes `setopt menucomplete' cycle through the history;
the `return 0' are an attempt to stop the accursed beeping, but that does
not work for some reason.  Someone more immersed in the completion code
than I will have to work out the other problems; I don't have more time
this morning to fiddle with it.

Index: Completion/Commands/_history_complete_word
===================================================================
--- Completion/Commands/_history_complete_word	2001/02/28 17:05:07	1.24
+++ Completion/Commands/_history_complete_word	2001/03/26 16:14:23
@@ -56,19 +56,32 @@
     if [[ "$direction" == 'older' ]]; then
       if [[ compstate[old_insert] -eq $_hist_menu_length ||
             "$_hist_stop" == 'oldest' ]]; then
-        _hist_stop='oldest'
         [[ "$stop" = verbose ]] &&
           _message 'beginning of history reached'
+	if [[ -n "$stop" ]]; then
+	  _hist_stop='oldest'
+	else
+	  compstate[old_list]=keep
+	  (( compstate[insert] = 1 ))
+	  return 0
+	fi
       elif [[ "$_hist_stop" == 'newest' ]]; then
         zle -Rc
         _history_complete_word_gen_matches
       else
         compstate[old_list]=keep
         (( compstate[insert] = compstate[old_insert] + 1 ))
+	return 0
       fi
     elif [[ "$direction" == 'newer' ]]; then
       if [[ compstate[old_insert] -eq 1 || "$_hist_stop" == 'newest' ]]; then
-        _hist_stop='newest'
+	if [[ -n "$stop" ]]; then
+          _hist_stop='newest'
+	else
+	  compstate[old_list]=keep
+	  (( compstate[insert] = $_hist_menu_length ))
+	  return 0
+	fi
         [[ "$stop" = verbose ]] && _message 'end of history reached'
       elif [[ "$_hist_stop" == 'oldest' ]]; then
         zle -Rc
@@ -76,6 +89,7 @@
       else
         compstate[old_list]=keep
         (( compstate[insert] = compstate[old_insert] - 1 ))
+	return 0
       fi
     fi
   else

-- 
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   

Re: Completing strings from history?

[Adam Spiers]

John Cooper (john.cooper@eu.citrix.com) wrote:
> Peter Stephenson <pws@csr.com> writes:
>  > > Typing `foo<ESC-/>' (bound to _history-complete-older) finds the most recent
>  > > word in the history beginning "foo".  Typing <ESC-/> again appears to do
>  > > nothing.
>  > > 
>  > > Is it possible to set things up so that repeatedly typing <ESC-/> cycles back
>  > > through all matches in the history?  (ala Emacs' dabbrev-expand)
>  > 
>  > You can do this by setting the `stop' style, which is so called because it
>  > stops when it has reached as far back into the history as it can (unlike
>  > normal menu completion which would continue cycling).
>  > 
>  >   zstyle ':completion:history-words:*' stop 1

Actually the intention was that repeatedly typing <ESC-/> always
cycled back, and that the stop style would stop cycling when it hit
the end-stops.  In other words, the default behaviour I intended when
I wrote it was the behaviour you want, but unfortunately it seems to
be broken.

> With the above zstyle, I find that hitting <ESC-/> after having reached the
> oldest history item prohibits <ESC-,> from taking my forwards again, and
> similarly, hitting <ESC-,> after cycling forwards to the most recent item
> prohibits <ESC-/> from taking me backwards again.

This is also a bug, I think.

> Two more questions:
> 
> 1. Is it possible to turn off the beep that's emitted every time I
>    type <ESC-/>?

This is maybe also a bug.  Argh!  It doesn't happen for me, presumably
because of one of the other zstyles I have set.  Not sure which
though.

> 2. Can all matching words be displayed as per normal completions
>    (then I'd see whether it's worth continuing to bang on <ESC-/> a
>    few more times)?

The `list' style controls that.

I think the reason this is all such a mess is because there's no
internal mechanism for controlling the behaviour of automenu when it
reaches the start or end of the match list, so it had to be
reimplemented in the shell function.  Ideally the `stop' style would
be implemented in the core of the completion code to control this, and
which would greatly simplify the current nastiness that is
_history_complete_word.  It would also leave the core engine in charge
of deciding when to generate the match list, rather than the current
_history_complete_word_gen_matches.

We could also then move the verbosity control from the `stop' style
(which can currently be `true' or `verbose') into the `verbosity'
style, which would make much more sense.

Sven? ;-)

Incidentally, the `Completion System Configuration' section in the
info pages is enormous; how about splitting it up into smaller chunks?
That way the xrefs from the `Style and Tag Index' would be much more
helpful, as they would land you directly on (or at least, a lot closer
to) the text concerning the style or tag you are looking up.  Or can
the info format do something equivalent to <a name="..."> ?

Sorry, this is getting a bit -worker-ish again...