Provide documentation and templates to write extensions

[ghost]

Could you write a standard document or example on developing sliver extensions (C++/Go)? If so, everyone could follow this standard to develop and contribute plugins. Wouldn't that be a very cool thing?

[rkervella]

We plan on making a repo with bootstrap template for extensions in different languages, but that's not done yet. So far there's no official documentation afaik, only community created ones like this one.

[ghost]

When is the bootstrap template expected to be available, thank you at the same time

[rkervella]

No ETA.

[maxlandon]

@moloch-- @rkervella

Here is one stone to kill n birds:

https://github.com/rsteube/carapace-spec

Use this as the schema for the command syntax of extensions (don't get me wrong: just for the command field of the extension spec).

As well, include the now widely used directive$shema path/to/yaml/json/schema into the extensions template root file.

Advantages:

• The spec above is meant to be consistently parsed into cobra command trees, for any shell. Since everything in Sliver is now a cobra command, using this spec ensures that everything will be parsed correctly.
• You can declare commands, flags and positionals with all possible specs and variants.
• you end up having not only a command syntax spec for your extensions, but you also get free completion for them, at arbitrary levels of complexity.
• Totally opt-in: people don't even have to know that this is a completer spec, since it's first and foremost a command tree declaration spec.
• Including the s$shema directive in the extension file provides validation, documentation and completion within editors with support for it.

Disadvantages for now:

• Only supports YAML syntax. Might be solved in the short-to-middle term. See json support carapace-sh/carapace-spec#150