Macro dynparser::ref_rule

macro_rules! ref_rule {
    ($e:expr) => { ... };
}

This will create a subexpression referring to a “rule name”

#[macro_use]  extern crate dynparser;

fn main() {
    let rules = rules!{
       "main" => ref_rule!("3a"),
       "3a"   => lit!("aaa")
    };

    assert!(dynparser::parse("aaa", &rules).is_ok())
}