Struct winnow::combinator::Repeat

pub struct Repeat<P, I, O, C, E>
where
    P: Parser<I, O, E>,
    I: Stream,
    C: Accumulate<O>,
    E: ParserError<I>,
{ /* private fields */ }

Implementation of repeat

Implementations

impl<ParseNext, Input, Output, Error> Repeat<ParseNext, Input, Output, (), Error>

where ParseNext: Parser<Input, Output, Error>, Input: Stream, Error: ParserError<Input>,

pub fn fold<Init, Op, Result>( self, init: Init, op: Op ) -> impl Parser<Input, Result, Error>

where Init: FnMut() -> Result, Op: FnMut(Result, Output) -> Result,

Repeats the embedded parser, calling g to gather the results

This stops before n when the parser returns ErrMode::Backtrack. To instead chain an error up, see cut_err.

Arguments

• init A function returning the initial value.
• g The function that combines a result of f with the current accumulator.

Warning: If the parser passed to fold accepts empty inputs (like alpha0 or digit0), fold_repeat will return an error, to prevent going into an infinite loop.

Example

Zero or more repetitions:

use winnow::combinator::repeat;

fn parser(s: &str) -> IResult<&str, Vec<&str>> {
  repeat(
    0..,
    "abc"
  ).fold(
    Vec::new,
    |mut acc: Vec<_>, item| {
      acc.push(item);
      acc
    }
  ).parse_peek(s)
}

assert_eq!(parser("abcabc"), Ok(("", vec!["abc", "abc"])));
assert_eq!(parser("abc123"), Ok(("123", vec!["abc"])));
assert_eq!(parser("123123"), Ok(("123123", vec![])));
assert_eq!(parser(""), Ok(("", vec![])));

One or more repetitions:

use winnow::combinator::repeat;

fn parser(s: &str) -> IResult<&str, Vec<&str>> {
  repeat(
    1..,
    "abc",
  ).fold(
    Vec::new,
    |mut acc: Vec<_>, item| {
      acc.push(item);
      acc
    }
  ).parse_peek(s)
}

assert_eq!(parser("abcabc"), Ok(("", vec!["abc", "abc"])));
assert_eq!(parser("abc123"), Ok(("123", vec!["abc"])));
assert_eq!(parser("123123"), Err(ErrMode::Backtrack(InputError::new("123123", ErrorKind::Many))));
assert_eq!(parser(""), Err(ErrMode::Backtrack(InputError::new("", ErrorKind::Many))));

Arbitrary number of repetitions:

use winnow::combinator::repeat;

fn parser(s: &str) -> IResult<&str, Vec<&str>> {
  repeat(
    0..=2,
    "abc",
  ).fold(
    Vec::new,
    |mut acc: Vec<_>, item| {
      acc.push(item);
      acc
    }
  ).parse_peek(s)
}

assert_eq!(parser("abcabc"), Ok(("", vec!["abc", "abc"])));
assert_eq!(parser("abc123"), Ok(("123", vec!["abc"])));
assert_eq!(parser("123123"), Ok(("123123", vec![])));
assert_eq!(parser(""), Ok(("", vec![])));
assert_eq!(parser("abcabcabc"), Ok(("abc", vec!["abc", "abc"])));

Trait Implementations

impl<P, I, O, C, E> Parser<I, C, E> for Repeat<P, I, O, C, E>

where P: Parser<I, O, E>, I: Stream, C: Accumulate<O>, E: ParserError<I>,

fn parse_next(&mut self, i: &mut I) -> PResult<C, E>

Take tokens from the Stream, turning it into the output

fn parse_peek(&mut self, input: I) -> IResult<I, O, E>

Take tokens from the Stream, turning it into the output

fn by_ref(&mut self) -> ByRef<'_, Self>

where Self: Sized,

Treat &mut Self as a parser

fn value<O2>(self, val: O2) -> Value<Self, I, O, O2, E>

where Self: Sized, O2: Clone,

Produce the provided value

fn default_value<O2>(self) -> DefaultValue<Self, I, O, O2, E>

where Self: Sized, O2: Default,

Produce a type’s default value

fn void(self) -> Void<Self, I, O, E>

where Self: Sized,

Discards the output of the Parser

fn output_into<O2>(self) -> OutputInto<Self, I, O, O2, E>

where Self: Sized, O: Into<O2>,

Convert the parser’s output to another type using std::convert::From

fn recognize(self) -> Recognize<Self, I, O, E>

where Self: Sized, I: Stream,

Produce the consumed input as produced value.

fn with_recognized(self) -> WithRecognized<Self, I, O, E>

where Self: Sized, I: Stream,

Produce the consumed input with the output

fn map<G, O2>(self, map: G) -> Map<Self, G, I, O, O2, E>

where G: FnMut(O) -> O2, Self: Sized,

Maps a function over the output of a parser

fn try_map<G, O2, E2>(self, map: G) -> TryMap<Self, G, I, O, O2, E, E2>

where Self: Sized, G: FnMut(O) -> Result<O2, E2>, I: Stream, E: FromExternalError<I, E2>,

Applies a function returning a Result over the output of a parser.

fn verify_map<G, O2>(self, map: G) -> VerifyMap<Self, G, I, O, O2, E>

where Self: Sized, G: FnMut(O) -> Option<O2>, I: Stream, E: ParserError<I>,

Apply both Parser::verify and Parser::map.

fn flat_map<G, H, O2>(self, map: G) -> FlatMap<Self, G, H, I, O, O2, E>

where Self: Sized, G: FnMut(O) -> H, H: Parser<I, O2, E>,

Creates a parser from the output of this one

fn parse_to<O2>(self) -> ParseTo<Self, I, O, O2, E>

where Self: Sized, I: Stream, O: ParseSlice<O2>, E: ParserError<I>,

Apply std::str::FromStr to the output of the parser

fn verify<G, O2>(self, filter: G) -> Verify<Self, G, I, O, O2, E>

where Self: Sized, G: FnMut(&O2) -> bool, I: Stream, O: Borrow<O2>, O2: ?Sized, E: ParserError<I>,

Returns the output of the child parser if it satisfies a verification function.

fn context<C>(self, context: C) -> Context<Self, I, O, E, C>

where Self: Sized, I: Stream, E: AddContext<I, C>, C: Clone + Debug,

If parsing fails, add context to the error

fn complete_err(self) -> CompleteErr<Self>

where Self: Sized,

Transforms Incomplete into Backtrack

fn err_into<E2>(self) -> ErrInto<Self, I, O, E, E2>

where Self: Sized, E: Into<E2>,

Convert the parser’s error to another type using std::convert::From