How to Use nom for Parser Combinators in Rust

Use the nom crate to build parsers by composing small functions that return results and handle input strings.

Use the nom crate by defining parser functions that return Result<(_, &str), Error> and composing them with combinators like nom::combinator::map.

use nom::{IResult, bytes::complete::tag, combinator::map};

fn parse_hello(input: &str) -> IResult<&str, &str> {
    map(tag("hello"), |_| "greeting")(input)
}

fn main() {
    let result = parse_hello("hello world");
    assert_eq!(result, Ok((" world", "greeting")));
}