Function winnow::combinator::preceded

source · 
pub fn preceded<I, O1, O2, E: ParserError<I>, F, G>(
    first: F,
    second: G,
) -> impl Parser<I, O2, E>
where
    I: Stream,
    F: Parser<I, O1, E>,
    G: Parser<I, O2, E>,
Expand description

Sequence two parsers, only returning the output from the second.

§Arguments

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

See also seq to generalize this across any number of fields.

§Example

use winnow::combinator::preceded;
use winnow::token::tag;

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

assert_eq!(parser.parse_peek("abcefg"), Ok(("", "efg")));
assert_eq!(parser.parse_peek("abcefghij"), Ok(("hij", "efg")));
assert_eq!(parser.parse_peek(""), Err(ErrMode::Backtrack(InputError::new("", ErrorKind::Tag))));
assert_eq!(parser.parse_peek("123"), Err(ErrMode::Backtrack(InputError::new("123", ErrorKind::Tag))));