This looks both cool and over-engineered. For some reason it gives me a bit of flashback to Java6 days of EE Bean servers though with crates upon crates.

Plus take the winnow library parser example. I’m not sure it’s gonna be easier to follow or debug than a standard recursive descent parser:

    fn hex_primary(input: &mut &str) -> Result<u8> {
        take_while(2, |c: char|  c.is_ascii_hexdigit())
            .try_map(|input| u8::from_str_radix(input, 16))
            .parse_next(input)
    }