Hello Peter, thank you for your suggestion. Following it I was able to
write:

compdef _docker xy=_docker_image_commands

that kind of work for the first word, the problem is that the second word
is not completed correctly since it tries again to use  _docker_image_commands
instead of whaterver it should have called.
The only functions defined inside the file that
/usr/share/zsh/vendor-completions/_docker match the word image are:

__docker_complete_images
__docker_complete_images_filters
__docker_image_commands
__docker_image_subcommand

so there isn't a more general completion function like _docker_image that
takes care of the completion for docker image [xx [yy]...], but there are
various functions called from __docker_subcommand inspecting the
array $words. What I would need, I think, is the ability to populate from
another completion function this array adding as first argument the value
"image", so that:

compadd _docker  mydockerwrapper=docker

would make __docker_subcommand   behave as if the command line contained
not only "docker" but "docker image", something like:

compadd _docker  mydockerwrapper="docker image"

that is obviously wrong because "docker image" it is not a correct service
name, I wrote it just to illustrate my point



2018-03-02 11:51 GMT+01:00 Peter Stephenson <p.stephenson@samsung.com>:

> From: Peter Stephenson <p.stephenson@samsung.com>
> To: Pier Paolo Grassi <pierpaolog@gmail.com>
> Cc: zsh-users@zsh.org
> Subject: Re: alias of completion
> Date: Fri, 2 Mar 2018 10:47:34 +0000
> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu)
> Organization: SCSC
>
> On Fri, 2 Mar 2018 10:31:57 +0100
> Pier Paolo Grassi <pierpaolog@gmail.com> wrote:
> > One thing I was never been able to accomplish though, is: what if I
> > want a custom function, say:
> >
> > mydockerwrapper(){}
> >
> > behave, for completion's sake, like, let's say:
> >
> > docker ls
> >
> > so that if I try to complete after
> >
> > mydockerwrapper <TAB>
> >
> > I get the same suggestion that I would get after docker ls, and if I
> > have
> >
> > mydockerwrapper xx <TAB>
> >
> > I get the same completion that I would get after  docker ls xx, and
> > so on.
>
> You need a bit of help from the completion function in
> question to do this.  The feature in question is "services": I just
> looked at the docker completion and it does support this.
>
> You'll need to do something like
>
> compdef _docker mydockerwrapper=docker_service_complete_ls_filters
>
> where the thing on the right of the "=" is an appropriate docker
> completion function without the "_" (search for _$service for the code
> in _docker supporting this).
>
> pws
>



-- 
Pier Paolo Grassi
email: pierpaolog@gmail.com
linkedin: https://www.linkedin.com/in/pier-paolo-grassi-19300217
fondatore: https://www.meetup.com/it-IT/Machine-Learning-TO