Support for completion in other shells (fish, sh, etc.)

[hasit]

Hello,

I was going through the repo (I am using cli for my new project) and I found that it supports generation of bash and zsh completion files automatically. That is pretty amazing. Is there a way to support other shells (e.g. fish, sh)? I am an avid fish shell user and have been using it since a long time.

I would like to propose implementation of EnableCompletion flag instead of EnableBashCompletion flag to accept a string for supported shells (like bash, zsh, fish, sh, ...) and generate autocomplete file for the mentioned shell.

If it is a desirable feature, I would like to brainstorm the implementation with the author and community members and take the initial steps towards its development.

[jszwedko]

Hi @hasit!

I think it would be great to support fish and other shells. I think your proposed change to the interface makes sense. I'd be happy to discuss further and review any pull requests introducing this.

[hasit]

Thank you @jszwedko.

To start off, I forked the repo and started reading the App interface and how it accepts parameters. My question is, how does EnableBashCompletion bool variable translate into generating autocomplete file? I do not see a function that is doing that. It'd be very helpful if you could explain the flow from the point of setting to generation of the autocomplete file.

To aid this enhancement, I would like to add

• In type App struct, change EnableBashCompletion bool -> EnableCompletion bool to accommodate all (supported) shells.
• In type App struct, add CompletionShells []string to accept which shell completion scripts the user wants to generate. For example, when writing a program in Go using cli, the user can write

...
app.EnableCompletion = true
app.CompletionShells = []string{"zsh", "fish", "bash"}
…

and cli will generate autocompletion scripts for all three shells.

[jszwedko]

Hi @hasit!

We'll want to maintain (but deprecate) EnableBashCompletion to support backwards compatibility for now, but I think your suggested fields make sense. We could simplify slightly and just do CompletionShells (if it is empty disable).

As far as for the current flow, it looks something like:

• Programmer enables bash completion via EnableBashCompletion
• User installs https://github.com/codegangsta/cli/blob/master/autocomplete/bash_autocomplete as like /etc/bash_completion.d/<program name> (this would commonly be done by a package or install script)
• When the user tries to tab complete, it will call the binary with --generate-bash-completion
• codegangsta/cli intercepts this and calls BashComplete which defaults to DefaultAppComplete (https://github.com/codegangsta/cli/blob/bc465becccd1d527002fda095fc3c19d9c115029/help.go#L119-L125)
• Bash interprets this result as a list of tokens that can appear next

Currently this only works for subcommands, but could be expanded to handle flags.

Let me know if this makes things clearer!

[saschagrunert]

I would like to bring this topic back in the table, because I think a fish completion should be doable relatively straight forward via code generation. WDYT?

[coilysiren]

I absolutely think we can add fish completion! It should be an easy PR to add into the 1.X series 👍

[stale[bot]]

This issue or PR has been automatically marked as stale because it has not had recent activity. Please add a comment bumping this if you're still interested in it's resolution! Thanks for your help, please let us know if you need anything else.

[coilysiren]

Bumping since this is low-lift to add 🙏

[stale[bot]]

This issue or PR has been bumped and is no longer marked as stale! Feel free to bump it again in the future, if it's still relevant.

[stale[bot]]

This issue or PR has been automatically marked as stale because it has not had recent activity. Please add a comment bumping this if you're still interested in it's resolution! Thanks for your help, please let us know if you need anything else.

[stale[bot]]

Closing this as it has become stale.

[tionis]

This should still be very relevant. Can I bump this?

[stale[bot]]

This issue or PR has been bumped and is no longer marked as stale! Feel free to bump it again in the future, if it's still relevant.

[dearchap]

It appears that fish completion was already added in 2.x. Do we want to keep the dynamic auto complete feature in cli or move to a generated one like what kubectl does.

kubectl completion fish | source