Parsing manual pages for auto-completion

[dundalek]

This is not an immediate concern but I am creating an issue for discussion and to collect currently existing approaches and maybe for someone to take a stab at it.

Parsing manual pages is a messy business since there is no single standard and there are many slight variations.

Existing approaches:

• Only project I am currently aware to attempt this is fish with fish_update_completions (source here).
• Other project is explainshell but it does not handle command grammars so it is not a suitable approach (it could generate invalid suggestions).

What I imagine:

• If completion definitions for a command are not available then try to parse man command or command --help or command -h
• There are many variations so using a high-level parsing library like Instaparse is preferred. We can define different variant of parsing rules and reuse the common rules.
• Docopt seems to be most formal description of command line arguments, so it makes sense to start with parsing its format, then extend to other manual pages in the wild.

[millettjon]

Something like compleat but in clojure would be useful.

[millettjon]

Could spec be used to generate completions?

[dundalek]

Compleat looks neat, but it does not have a repository of completions so I don't see much value in integrating it.

I once played with using spec to parse argument for a CLI app and I think its doable. Once you have a spec it should be possible to write a completion generator for it. It's a kind of a long shot though.

[dundalek]

Not going to be working on this anytime soon, closing for now.