multiple policies, effects, matchers support

[GopherJ]

No description provided.

[hsluoyz]

How to enforce for multiple matchers?

[GopherJ]

@hsluoyz My idea is to use regexp to extrat pn from matcher.

regexp

// compile only once
 static ref EXR_P: Regex = Regex::new(r"\b(?P<ptype>p\d*)_").unwrap();

extract function

pub fn extract_ptype_from_matcher(m: &str) -> Option<String> {
    let mut ptype: Option<String> = None;

    for caps in EXR_P.captures_iter(m) {
        if ptype.is_none() {
            ptype = Some(caps["ptype"].to_string());
            continue;
        } else if Some(&caps["ptype"]) == ptype.as_deref() {
            continue;
        } else {
            panic!("one matcher can only contain one type of policy. eg. p, p2, p3...");
        }
    }

    return ptype;
}

[GopherJ]

once ptype is extracted, we can then know which policy to use (p1, p2, p3, p...n), then we will be able to calculate the value for m1, m2, m3`...

The key thing here is to use something like IndexMap instead of HashMap which will keep order, otherwise maybe it'll first calculate the value of m2 but m2 relies on m, m1...

[GopherJ]

A first version will be in #123