Re: completion but extra options allowed

[Sven Wischnowsky <wischnow@informatik.hu-berlin.de>]

[ moved to zsh-workers ]

Bart Schaefer wrote:

> ...
>
> Yes, I noticed just after posting that this isn't actually handled by
> _mutt and _mailboxes.  In attempting to do something with this, I found
> some rather strange things going on in the guts of the completion.
> 
> _mutt calls _arguments in the expected way.
> 
> _arguments calls "_description arguments expl mailbox" which sets expl
> to (-J -default-).
> 
> _arguments then calls "_mailboxes -J -default-" which (after setting up
> the cache) calls "_wanted files expl 'mailbox specification'" which again
> sets expl to (-J -default-).
> 
> _mailboxes then calls "compadd -J -default- -J -default- - ..." which
> seems a bit odd.  The first -J -default- is from "$@" and the second is
> of course "$expl[@]".  Is that really doing the right thing?

1) Depending of the setting of the group-name style you may have gotten
different names.
2) Yes, that's ok. The _description in _mailboxes sets up a default
description that may be overridden by a calling function.
3) Depending on the implementors preferences, he may or may not change 
the '-f+:mailbox:_mailboxes' to '-f+:mailbox: _mailboxes', which will
make _arguments *not* give a description to _mailboxes (i.e., then you 
only get the second one).


In another message:

> ...
> 
> One thing that makes this difficult is that _path_files does not accept
> the -i option of compadd, only the -P option.

All completion I can think of are written so that they work nicely
when PREFIX/IPREFIX (and SUFFIX/ISUFFIX) are set up appropriately.

> However, even calling
> 
> compadd -i + -f -W ~/Mail
> 
> directly does not accomplish what I expected it to.  Is this a bug, or am
> I missing something?  What IS the compadd equivalent of
> 
> compctl -x 's[+] c[-1,-f],s[-f+]' -W ~/Mail -f ...

-i just *adds* some string to IPREFIX. It is really only useful when
used with -U, i.e. by functions that have to do all the matching
themselves (because then IPREFIX isn't used by the completion code and 
-i can be used to tell it about an ignored prefix).

So, the right way to do the same as that compctl would be:

  if compset -P '+|-f+' || [[ $words[CURRENT-1] = -f ]]; then
    _files -W ~/Mail
  else
    ...
  fi

where the compset sets up PREFIX/IPREFIX for us.

Bye
 Sven


--
Sven Wischnowsky                         wischnow@informatik.hu-berlin.de