Function preceded 

pub fn preceded<I, O1, O2, E, F, G>(first: F, second: G) -> impl FnMut(I)
where
    E: ParseError<I>,
    F: Parser<I, O1, E>,
    G: Parser<I, O2, E>,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Matches an object from the first parser and discards it, then gets an object from the second parser.

Arguments

• first The opening parser.
• second The second parser to get object.

use nom::sequence::preceded;
use nom::bytes::complete::tag;

let mut parser = preceded(tag("abc"), tag("efg"));

assert_eq!(parser("abcefg"), Ok(("", "efg")));
assert_eq!(parser("abcefghij"), Ok(("hij", "efg")));
assert_eq!(parser(""), Err(Err::Error(("", ErrorKind::Tag))));
assert_eq!(parser("123"), Err(Err::Error(("123", ErrorKind::Tag))));