Here is some rust code for how i did it (its part of a larger program so won't compile on its own)
its initally called with precedence_level=0
:
let precedence: BTreeMap<&'static str, i16> = [
    ("=~", 1), ("-=", 1), ("+=", 1), ("*=", 1), ("/=", 1), ("=", 1),
    ("^=", 1), ("**=", 13), ("|=", 1), ("&=", 1), ("%=", 1),
    ("<<=", 1), (">>=", 1), ("||", 2), ("&&", 3), ("|", 4), ("^", 5),
    ("&", 6), ("==", 7), ("!=", 7), ("<", 8), (">", 8), ("<=", 8),
    (">=", 8), ("<<", 9), (">>", 9), ("+", 10), ("-", 10),
    ("*", 11), ("/", 11), ("%", 11), ("**", 12), ("..", 15),
]
    .into_iter()
    .collect();
let right_associative: BTreeMap<&'static str, bool> = [
    ("=", true), ("**", true), ("**=", true), ("=~", true),
    ("+=", true), ("-=", true), ("*=", true), ("/=", true),
    ("^=", true), ("|=", true), ("&=", true), ("%=", true),
    ("<<=", true), (">>=", true),
]
    .into_iter()
    .collect();let precedence: BTreeMap<&'static str, i16> = [
    ("=~", 1), ("-=", 1), ("+=", 1), ("*=", 1), ("/=", 1), ("=", 1),
    ("^=", 1), ("**=", 13), ("|=", 1), ("&=", 1), ("%=", 1),
    ("<<=", 1), (">>=", 1), ("||", 2), ("&&", 3), ("|", 4), ("^", 5),
    ("&", 6), ("==", 7), ("!=", 7), ("<", 8), (">", 8), ("<=", 8),
    (">=", 8), ("<<", 9), (">>", 9), ("+", 10), ("-", 10),
    ("*", 11), ("/", 11), ("%", 11), ("**", 12), ("..", 15),
]
    .into_iter()
    .collect();
let right_associative: BTreeMap<&'static str, bool> = [
    ("=", true), ("**", true), ("**=", true), ("=~", true),
    ("+=", true), ("-=", true), ("*=", true), ("/=", true),
    ("^=", true), ("|=", true), ("&=", true), ("%=", true),
    ("<<=", true), (">>=", true),
]
    .into_iter()
    .collect();


async fn parse_expression(&mut self, precedence_level:i16) -> Object {
    // Scope parse_primary call to release mutable borrow of self before the loop
    let mut left = self.parse_primary().await;
    while self.pos<self.tokens.len() &&
        self.tokens[self.pos].name != TokenType::Eol &&
        self.tokens[self.pos].name != TokenType::BracketOpen &&
        self.tokens[self.pos].name != TokenType::BracketClose &&
        self.tokens[self.pos].name != TokenType::ParClose {
        let op=self.tokens[self.pos].value.clone();
        let mut prec=-1;
        if self.precedence.contains_key(op.clone().as_str()){
            prec=self.precedence[op.clone().as_str()];
        }

        if prec < precedence_level {
            break;
        }
        let mut is_right=false;
        if self.right_associative.contains_key(op.clone().as_str()){
            is_right=self.right_associative[op.clone().as_str()];
        }
        let next_precedence_level=if is_right {prec} else {prec+1};
        self.pos+=1;
        let right=self.parse_expression(next_precedence_level).await;
        let op_node =AST::new("operator", op.clone()).await;
        AST::add_child(&op_node, left).await;
        AST::add_child(&op_node, right).await;
        left= Arc::clone(&op_node);
    }
    return left;
}