You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: utils.rs
    path of file: ./repos/tools/xtask/coverage/src/symbols
    
    the code of the file until where you have to start completion: pub fn parse_str<'a>(input: &'a str, s: &'a str) -> Option<(&'a str, &'a str)> {
    input
        .strip_prefix(s)
        .map(|stripped| (stripped, &input[0..s.len()]))
}

pub fn parse_until_chr(in
    
pub fn parse_until_chr(input: &'_ str, f: impl Fn(char) -> bool) -> Option<(&'_ str, &'_ str)> {
    let mut qty = 0;

    for chr in input.chars() {
        if f(chr) {
            break;
        }

        qty += chr.len_utf8();
    }

    if qty > 0 {
        Some((&input[qty..], &input[0..qty]))
    } else {
        None
    }
}