Function winnow::multi::fold_many1
source · pub fn fold_many1<I, O, E, F, G, H, R>(
f: F,
init: H,
g: G
) -> impl Parser<I, R, E>where
I: Stream,
F: Parser<I, O, E>,
G: FnMut(R, O) -> R,
H: FnMut() -> R,
E: ParseError<I>,
Expand description
Repeats the embedded parser, calling g
to gather the results.
This stops on ErrMode::Backtrack
if there is at least one result. To instead chain an error up,
see cut_err
.
Arguments
f
The parser to apply.init
A function returning the initial value.g
The function that combines a result off
with the current accumulator.
Warning: If the parser passed to many1
accepts empty inputs
(like alpha0
or digit0
), many1
will return an error,
to prevent going into an infinite loop.
Example
use winnow::multi::fold_many1;
use winnow::bytes::tag;
fn parser(s: &str) -> IResult<&str, Vec<&str>> {
fold_many1(
"abc",
Vec::new,
|mut acc: Vec<_>, item| {
acc.push(item);
acc
}
).parse_next(s)
}
assert_eq!(parser("abcabc"), Ok(("", vec!["abc", "abc"])));
assert_eq!(parser("abc123"), Ok(("123", vec!["abc"])));
assert_eq!(parser("123123"), Err(ErrMode::Backtrack(Error::new("123123", ErrorKind::Many))));
assert_eq!(parser(""), Err(ErrMode::Backtrack(Error::new("", ErrorKind::Many))));