detect if command has a completion function

detect if command has a completion function

[vapnik spaknik]

Hi,
    how can I detect if a given command has a completion function, from within another function?
I want to loop over many commands quickly, so I want to avoid resorting to searching directories with find if possible.

The reason I need this capability is to help with a function I've written for cleaning up .zshrc files.
I tend to collect lots of "compdef _gnu_generic cmd1 cmd2..." lines in my .zshrc, but many of the commands flagged for completion with _gnu_generic are not present on other systems where I install the same .zshrc. I wrote a function which checks the commands mentioned in those "compdef _gnu_generic" lines, and removes any that are not present on the system:

function cleanup-compdefs() {
    local okcmds=() numcols=120
    for cmd in ${(i)$(grep -e "^compdef _gnu_generic" ~/.zshrc|sed 's/compdef _gnu_generic//')}; do
	if which ${cmd} &>/dev/null; then
	    okcmds+="$(basename ${cmd})"
	fi
    done
    local line i=1
    while [[ ${i} -le ${#okcmds} ]]; do
	line="compdef _gnu_generic"
	while [[ ${#line} -lt ${numcols} ]]; do
	    line+=" ${okcmds[${i}]}"
	    i=$((${i} + 1))
	done
	echo "${line}"
    done
}

However, I also want it to check which of the commands already have completion functions defined, so that they can also be removed.
Can anyone help?

Re: detect if command has a completion function

[Marc Cornellà]

>     how can I detect if a given command has a completion function, from within another function?
> I want to loop over many commands quickly, so I want to avoid resorting to searching directories with find if possible.
>
> The reason I need this capability is to help with a function I've written for cleaning up .zshrc files.
> I tend to collect lots of "compdef _gnu_generic cmd1 cmd2..." lines in my .zshrc, but many of the commands flagged for completion with _gnu_generic are not present on other systems where I install the same .zshrc.

You can use the `$_comps` array which controls which completion
function is assigned to a command.
For example, the completion function for `ls` is `_ls`:

  $ echo $_comps[ls]
  _ls

And so on

Marc

Re: detect if command has a completion function

[vapnik spaknik]

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>On Saturday, August 29, 2020, 06:21:21 PM GMT+1, Marc Cornellà <marc.cornella@live.com> wrote:
>
>You can use the `$_comps` array which controls which completion
>function is assigned to a command.
>For example, the completion function for `ls` is `_ls`:
>
>  $ echo $_comps[ls]
>
>  _ls

Perfect, thankyou!


  

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Re: detect if command has a completion function

[Bart Schaefer]

On Sat, Aug 29, 2020 at 9:47 AM vapnik spaknik <vapniks@yahoo.com> wrote:
>
> The reason I need this capability is to help with a function I've written for cleaning up .zshrc files.
> ... I wrote a function which checks the commands mentioned in those "compdef _gnu_generic" lines, and removes any that are not present on the system:

Don't bother removing the compdef lines, just remove their results.
That way you won't have to add things back again if you install one of
those missing programs.

completed=( ${(k)_comps:#([^[:alnum:]]*)} )
installed=( ${(k)builtins} ${(k)functions} ${(k)commands} )
not_installed=( ${completed:|installed} )
unset '_comps['${^not_installed}']'

Just be sure you have done all your zmodloads and autoloads before
executing the above, or you'll remove completions for some builtins
and functions.

Older zsh will not have the ${name:|arrayname} syntax so you might
have to resort to

not_installed=( ${completed:#${~:-(${(j:|:)${(q)installed}})}} )

Re: detect if command has a completion function

[Bart Schaefer]

On Sat, Aug 29, 2020 at 11:33 AM Bart Schaefer
<schaefer@brasslantern.com> wrote:
>
>  Don't bother removing the compdef lines, just remove their results.

This could be taken a step further:

all_comps=( ${(v)_comps} )
completed=( ${(k)_comps:#-*} )
installed=( ${(k)builtins} ${(k)functions} ${(k)commands} )
not_installed=( ${completed:|installed} )
unset '_comps['${^not_installed}']'
used_comps=( ${(v)_comps} )
unused_comps=( ${all_comps:|used_comps} )
unfunction ${(k)functions:*unused_comps}

(Note the tweak to completed=(...), I think -* covers what needs ignoring.)