add basic implementation of tab completion

[umbynos]

Please check if the PR fulfills these requirements

• The PR has no duplicates (please search among the Pull Requests before creating one)
• The PR follows our contributing guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

• What kind of change does this PR introduce?

feature

• What is the current behavior?

#649

• What is the new behavior?

add completion with TAB press. At the current time, the feature is very basic and only work for bash. I'm planning to add compatibility with fish and zsh. I'll also try to add the completion for lib and cores.

• Does this PR introduce a breaking change?

No breaking change.
To try the feature it's required to run arduino-cli completion bash > completion.sh and then source completion.sh

• Other information:

---

See how to contribute

[ubidefeo]

recent versions of zsh allow for bash completion sourcing
bashcompinit and a source should be issued in the shell session init

https://computingforgeeks.com/how-to-source-bash-completion-script-file-in-zsh/

[umbynos]

fish sneak peek! It's also showing the description of the commands and subcommands.
But there's a problem: fish apparently does not support env variables with dash in the name. And unfortunately there are some env varibles with the dash in the name like __arduino-cli_comp_do_file_comp in the autogenerated file. I managed in "fixing" by changing - with _ manually in the file. but this solution is not feasible.

[umbynos]

Forgot to mention that also flags completion should work fine. As well as flag and subcommand description (only supported by fish and zsh)

[umbynos]

I think I succeed in fixing the problem with env vars naming and fish compatibility.
The PR for me Its ready. I've tried the completion with bash and fish. @ubidefeo or @rsora could you please try with zsh?

I also added a flag --no-description in order to disable description for commands and flags (it only works with fish).

To test it:

• Bash
  ./arduino-cli completion bash > arduino-cli.sh and then source arduino-cli.sh
• Fish
  ./arduino-cli completion fish > arduino-cli.fish and then source arduino-cli.fish
• Zsh
  ./arduino-cli completion zsh > _arduino-cli.zsh and then source _arduino-cli.zsh

Sourcing a script in ~/.zshrc, ~/.bashrc it's not recommended, but it's only for testing purposes.

The proper way to do it is to place arduino-cli.fish to ~/.config/fish/completions/ for fish, copy arduino-cli.sh to /etc/bash_completion.d/ for bash. The only way to make it work for zsh for me was to source it in ~.zshrc.

I still have not added fqbn, cores, libraries completion. They require more work and I think I'll do it in a following PR. Is it ok for you?

I still have to update the documentation accordingly. I'll do it as soon as I have your opinion on the PR.
😄

[ubidefeo]

Will not work under my zsh, @umbynos
let's look at it together when you're around

[umbynos]

I've fixed also zsh completion. It was not working because [ and ] needed escaping and I had to remove the # in front of compinit.
Should work now ☕

[ericonr]

I had missed the notification for this one, this is awesome! Great work! I tested the initial functionality, it seemed to work really well!

I know the PR is still in progress, but it could be interesting to add some notes on how to use this, specially for people building for distribution (that way the generated completion files can be packaged already in the correct places).

The functionality I tested is already pretty great, perhaps the --fbqn part can be left to another PR, as you mentioned? I can try to help with testting and development for that one. My main shell is Fish, let me know if you have anything requiring testing!

[umbynos]

Thank you! Currently I'm following this plan:

1. Make the completion work for zsh (I still have some problems in finding where to put the completion file)
2. Add testing for this functionality (https://brbsix.github.io/2015/11/29/accessing-tab-completion-programmatically-in-bash/)
3. Learn something about Homebrew and find a way to generate the completion file during the installation and place it in the correct place (depends on the shell used)(https://docs.brew.sh/Shell-Completion).
4. Maybe add a task in Taskfile to install the completion in the right place.
5. Add proper documentation

I'll try to improve the completion (add --fqbn, cores and libs completion) with another PR when this one will be ready and merged. I will certainly ask for your help, thank you!

[ericonr]

1. My distro seems to use /usr/share/zsh/site-functions/_alacritty for zsh completions. User generated ones probably go in ~/.local/share/zsh/site-functions, as long as they follow the logical paths.

2. Probably makes sense to store the completions for all the shells that can be used in MacOS, I think.

3. Seems reasonable!

[ubidefeo]

@ericonr
Apparently there are still some rough edges on Mac OS.
I for instance run Prezto and @umbynos and I haven't been able to make it work without sourcing the completion and its compdef line.
I confide in @umbynos to make it work :)

[umbynos]

@per1234 when you have time, could you please give a look to the documentation i've added please? 😄

[per1234]

Very nice @umbynos! I gave it a quick try with bash and zsh and it worked great.

I only have a few nitpicky suggestions for the documentation.

[rsora]

Tested with bash and zsh and it worked smoothly following the provided documentation.
Excellent!