nom_error.rs

#[macro_use]
extern crate nom;

use nom::alpha;
use nom::types::CompleteStr;
use nom::ErrorKind;

named!(block<CompleteStr, Vec<(CompleteStr, CompleteStr)>>,
    do_parse!(
        tag!("BEGIN") >>
        char!('\n') >>
        lines: return_error!(ErrorKind::Custom(0),many0!(line)) >>
        return_error!(ErrorKind::Custom(1), tag!("END")) >>
        char!('\n') >>
        (lines)
    ));

named!(line<CompleteStr, (CompleteStr, CompleteStr)>,
    do_parse!(
        a: alpha >>
        char!(',') >>
        b: alpha >>
        char!('\n') >>
        (a, b)
    ));

fn main() {
    const INPUT: &str = r#"BEGIN
hello,world
fo
END
"#;
    let res = block(CompleteStr(INPUT));
    println!("{:?}", res);
}