Positionals with special meaning

[pacak]

I'm trying to parse a structure that more or less looks like this:

enum Mode {
    Foo,
    Bar { baz: String }
}

Ideally, app foo parses to Mode::Foo and app bar quux parses to Mode::Bar { baz: "quux" }.

I've tried combining positional parsers and even implementing my own, but I'm pretty sure I'm
barking up the wrong tree. Is there a relatively simple, canonical way of doing this with bpaf?

[pacak]

Positional with a special meaning that changes the meaning of subsequent parsers is usually a
command and you combine them with construct!([foo, bar]).

See a complete example here: https://github.com/pacak/bpaf/blob/master/examples/git.rs