Function between 

pub fn between(
    open: &'static str,
    close: &'static str,
) -> impl Parser<String, Err = BetweenErr>

Takes a segment between a given opener and closer.

let mut input = ParserString::from("(abc) ");
let middle = between("(", ")").parse(&mut input);
assert!(middle.is_ok_and(|s| s == "abc"));