Adding support for Wasp completions in zsh

[infomiho]

We currently have bash completions support with wasp completion and wasp completion:generate > <your-chosen-directory>/wasp-completion.

wasp/waspc/cli/src/Wasp/Cli/Command/BashCompletion.hs

Line 16 in 2ed921a

bashCompletion :: Command ()

These completions are bash specific and don't work with zsh (default shell for our MacOS users). The user needs to add the following to their .zshrc to add support for bash-like completion:

autoload -U compinit && compinit -u
autoload bashcompinit && bashcompinit

We want to make our completion command aware that there are two different shells and help users with zsh to setup Wasp completions. The command should allow user to select which shell he uses and get the proper info how to setup completions.

For example, wasp completion zsh would instruct user with zsh how to setup completions.

We could take two routes:

1. Piggy-back on bash completions and instruct user how to enable it for zsh (quick and dirty)
2. Write our own native zsh completions code (proper way to do it details)

[infomiho]

I've go this working for me (it's pretty basic, since I'm new to zsh completions).

file: ~/.zshrc

fpath=($fpath ~/.completions)

file: ~/.completions/_wasp

#compdef _wasp wasp

function _wasp {
    local line

    _arguments -C \
        "1: :(new version waspls completion start db clean build telemetry deps dockerfile info)" \
        "*::arg:->args"

    case $line[1] in
        new)
            _wasp_new
        ;;
        db)
            _wasp_db
        ;;
    esac
}

function _wasp_new {
    _arguments \
        "1:project name:"
}

function _wasp_db {
    _arguments \
        "1: :(migrate-dev studio)"
}

[Martinsos]

Nice explanation!

I think we should be looking into solution number one -> go with bash autocompletion and just piggy back on it for zsh. As you said, we can ask users what they use, then give them correct instrutcions / do correct actions, and that is it.

Regarding the bash script you wrote -> I would rather we don't have duplicated logic for autocompletion. Right now we actually don't have much logic at all even in bash -> all logic is in Haskell, and bash just proxies it. So we really want sometihng simlar with zhs. Piggybacking on bash sounds like the best trade off between speed and what we get.

[AmberArr]

I use a similar script but reusing bash completion functionality.

#compdef wasp

local completions
local completion

IFS=$'\n' completions=($( COMP_LINE=$words wasp completion:list ))

for completion in $completions; do
    compadd -- $completion
done

But the bash completion now needs some improvement. wasp new <TAB> (there is a space after new) just gives me wasp new new.

Switching to optparse-applicative might be a option, and we can get free bash/zsh/fish completion and no more sync between cli and completion. But the code would look complex IMO.

[Martinsos]

Yeah, you are right, I think we should switch to optparse-applicative. It will make code more complex, but I think it is worth it.