Can I ignore order?

[RudolfVonKrugstein]

Hello everyone,

Given a grammar like this:

a = {"A"}
b = {"B"}
S = { (a | b)* }

Is it possible, to get a past-ast struct for S, like this:

#[derive(Debug, FromPest)]
#[pest_ast(rule(Rule::S))]
pub struct S {
  as: Vec<A>,
  bs: Vec<B>
}

#[derive(Debug, FromPest)]
#[pest_ast(rule(Rule::A))]
pub struct S {
}

#[derive(Debug, FromPest)]
#[pest_ast(rule(Rule::B))]
pub struct S {
}

In this example, I would like to count the as and bs, but I do not care for the order.

Can this be done?