frosch03.de/posts/2013-02-10-ZSH-Compeltion

giving frogblog zsh completion

I always was annoyed, that working with the frogblog was a pain. One has to type the correct subject name into the command line. Therefore you must first get a list of all the subjects by frogblog list.

I wondered always, how to enable completion inside my console. Because i use zsh as my shell, i show here how to enable completion for frogblog in zsh.

Completion Folders

The folder where zsh looks for completions are listed in the $fpath variable. You can add the completion file in one of the existing folders. I created ~/.zsh/complete and added the path to the $fpath. Here are the additional lines for .zshrc:

{% highlight bash %} fpath=(~/.zsh/complete $fpath) {% endhighlight %}

Also make sure that the compinit is autoloaded (what ever that means ;)) and that the right completion menu is known.

{% highlight bash %} autoload -U compinit compinit 

zstyle ':completion:*' menu select=2

{% endhighlight %}

Completion file for frogblog

Completion files are named with a starting '\_'. Here is the content of ~/.zsh/complete/_frogblog

{% highlight bash %} #compdef frogblog 

_frogblog() {
    local curcontext="\$curcontext" state line
    typeset -A opt_args

    _arguments \
        '1: :->action'\
        '*: :->subject'

    case \$state in
    action)
        _arguments '1:actions:(list publish delete)'
    ;;
    *)
        case \$words[2] in
        list)
        ;;
        publish)
            compadd "\$@" `ls *.hlog`
        ;;
        delete)
            compadd "\$@" `frogblog list | xargs`
        ;;

        *)
            _files
        esac
    esac
}

_frogblog "$@"

{% endhighlight %}

The _arguments need to be first an action, which can be of the list (list publish delete). For every one of these actions there are different argument to be submitted.

  • list - is the one that has no more arguments
  • publish - offers all files in the current directory end with .hlog
  • delete - offers the list that frogblog list would return

If you want to know more how this mechanism actually works, have a look at the page i found the most useful information about zsh completion: ZSH – Writing own completion functions.