Re: _files vs _path_files discussion (old thread)

[Adam Spiers <adam@spiers.net>]

Thanks for these explanations Bart, and apologies for missing the
thread the first time round.

Bart Schaefer (schaefer@candle.brasslantern.com) wrote:
> So you also need e.g.:
> 
> zstyle ':completion::complete:tar::directories' file-patterns '*(-/)'
> 
> You can of course replace :tar:: there with :*:*: to make all commands
> that use _files complete directories; but as Sven mentions in 9864,
> you may not want that, which is why the file-patterns are required to
> be given in the first place.

I've settled on the following for now, and it doesn't seem to have any
of the unwanted side-effects mentioned:

   # Include non-hidden directories in globbed file completions
   compstyle '::complete:*' \
     tag-order 'globbed-files directories' all-files 
   compstyle '::complete:*:*:directories' file-patterns '*~.*(-/)'

It's almost perfect ...  The only problem left is in the handling of
hidden directories; ideally, I would want hidden directories only to
appear when the leading `.' is specified manually, because I have so
many hidden directories in my home directory that they swamp the
initial completion list.  However, because they are not covered by the
file-patterns style for the directories tag, if I do:

   $ tar zxf .foodir/<TAB>

it's presumably using all-files, which has the initial problem of not
listing directories by default.  So what I'm really after is something
like:

   zstyle ':completion::complete:*:*:directories' \
     file-patterns '*(-/)'
   zstyle ':completion::complete:*:*:unhidden-directories' \
     file-patterns '*~.*(-/)'
   zstyle ':completion::complete:*' tag-order \
     'globbed-files unhidden-directories' \
     'globbed-files directories' \
     all-files

except that that doesn't work, presumably because you can't just dream
up new tags like that, and maybe you can't even mention tags twice in
tag-order.  So, is there a solution, and if not, would it be totally
unrealistic to allow something like the above zstyle code?  Actually,
even if that code worked, it still wouldn't quite do what I want,
because at the `.foodir/<TAB>' stage it would be completing from the
'globbed-files directories' bit (or would it?), which would mean that
it would list `.foodir/.bardir', which I wouldn't want it to.  Looks
like what I'm asking for would require considering each path component
separately.  Urgh.  Now my head's spinning.

> [*] Sven's suggested change was:
> } ... should we make the directories tag with its usual pattern be
> } tried automatically if the user explicitly sets the file-patterns tag
> } for globbed-files? Or should we do that only if the directories tag,
> } file-patterns style is given, but allow an empty value to stand for
> } `the normal pattern'?
> 
> I meant to reply to that and hadn't got around to it yet.
> 
> My short answer is that I don't think there's any good solution.  The
> tag-order style is going to be confusing no matter what we do; people
> are always going to wonder why, when they can see "directories" in the
> tag-order style, they still don't get any directories completed.  It's
> a case of intuition being at odds with logical semantics, and I can't
> think of any way to make the intuition work without ruining the logic.
> 
> Automatically adding directories when globbed-files is given only makes
> things cloudier; allowing an empty pattern to stand for '*(-/)' doesn't
> alleviate the need to provide the directories style, which is the real
> basis of the confusion.  So I think I'd leave the code as is, and put
> some kind of blaring all-caps text in the tag-order documentation:
> 
> NAMING A TAG IN TAG-ORDER DOES NOT CAUSE COMPLETIONS FOR THAT TAG TO BE
> GENERATED; RATHER, IT SORTS THE COMPLETIONS AFTER THEY ARE GENERATED.

I'd agree.  Actually, now I know the stuff in blaring all-caps, I
don't find it that confusing anyway.

> One additional thought:  It would be nice to be able to specify that
> _paths_ are completed, rather than merely directories; i.e. like the
> difference between "compctl -g '*(-/)'" and "compctl -/".  I'm not
> convinced that "zstyle *directories file-patterns '*(-/)'" does that.

What is the difference?  I can't see any, but I'm probably missing
something (again).

> Hrm, maybe even add "... BUT ONLY _IF_ ANY ARE GENERATED FOR THAT TAG."

Good plan.

Adam