Getting values multiple occurrences of group in order

[fabianfreyer]

I've got an ArgGroup that contains multiple values taking (optional) values, e.g.:

  --foo [<FOO>] 
  --bar <BAR>
  --baz <BAZ>
  --other-option

Here, the group contains ["foo", "bar", "baz"], but not other-option. Each can be specified multiple times, e.g.:

--foo --bar a --bar b --foo x --other-option --baz w

Now, my goal is to get a list of all (Id, Option<T>) pairs that are part of this group, keeping order intact:

vec![
    ("foo", None),
    ("bar", Some("a"),
    ("bar", Some("b")),
    ("foo", Some("x")),
    ("baz", Some("w")),
]

I'm not quite sure how I can do this, since using get_occurrences on the group just gets me the Id's, (need to downcast to clap_builder::util::id::Id), but that just gives me the Id's in order.

I've tried the following, which doesn't completely work, since get_occurrences seems to skip the foo when no value is given, and it doesn't make use of the argument group, but relies on hard-coded ids. Furthermore, because of #2419, it seems to skip the index of --foo where no argument is given.

let mut ids = ["foo", "bar", "baz"]
    .into_iter()
    .flat_map(|id| {
        let files = std::iter::zip(
            self.matches
                .get_occurrences::<String>(id)
                .unwrap_or_default()
                .map(|mut occurrence| occurrence.next()),
            self.matches.indices_of(id).unwrap_or_default(),
        )
        .map(move |(value, index)| (id, value, index));
        files
    })
    .collect::<Vec<(&str, Option<&String>, usize)>>();

ids.sort_by(|(_, _, a), (_, _, b)| a.cmp(b));

let result = ids
    .into_iter()
    .map(|(id, value, _)| (id, value))
    .collect::<Vec<(&str, String)>();

[epage]

For others, #2419 is where this conversation continued