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+//! General purpose combinators
+
+#![allow(unused_imports)]
+
+#[cfg(feature = "alloc")]
+use crate::lib::std::boxed::Box;
+
+use crate::error::{ErrorKind, FromExternalError, ParseError};
+use crate::internal::*;
+use crate::lib::std::borrow::Borrow;
+use crate::lib::std::convert::Into;
+#[cfg(feature = "std")]
+use crate::lib::std::fmt::Debug;
+use crate::lib::std::mem::transmute;
+use crate::lib::std::ops::{Range, RangeFrom, RangeTo};
+use crate::traits::{AsChar, InputIter, InputLength, InputTakeAtPosition, ParseTo};
+use crate::traits::{Compare, CompareResult, Offset, Slice};
+
+#[cfg(test)]
+mod tests;
+
+/// Return the remaining input.
+///
+/// ```rust
+/// # use nom::error::ErrorKind;
+/// use nom::combinator::rest;
+/// assert_eq!(rest::<_,(_, ErrorKind)>("abc"), Ok(("", "abc")));
+/// assert_eq!(rest::<_,(_, ErrorKind)>(""), Ok(("", "")));
+/// ```
+#[inline]
+pub fn rest<T, E: ParseError<T>>(input: T) -> IResult<T, T, E>
+where
+ T: Slice<RangeFrom<usize>>,
+ T: InputLength,
+{
+ Ok((input.slice(input.input_len()..), input))
+}
+
+/// Return the length of the remaining input.
+///
+/// ```rust
+/// # use nom::error::ErrorKind;
+/// use nom::combinator::rest_len;
+/// assert_eq!(rest_len::<_,(_, ErrorKind)>("abc"), Ok(("abc", 3)));
+/// assert_eq!(rest_len::<_,(_, ErrorKind)>(""), Ok(("", 0)));
+/// ```
+#[inline]
+pub fn rest_len<T, E: ParseError<T>>(input: T) -> IResult<T, usize, E>
+where
+ T: InputLength,
+{
+ let len = input.input_len();
+ Ok((input, len))
+}
+
+/// Maps a function on the result of a parser.
+///
+/// ```rust
+/// use nom::{Err,error::ErrorKind, IResult,Parser};
+/// use nom::character::complete::digit1;
+/// use nom::combinator::map;
+/// # fn main() {
+///
+/// let mut parser = map(digit1, |s: &str| s.len());
+///
+/// // the parser will count how many characters were returned by digit1
+/// assert_eq!(parser.parse("123456"), Ok(("", 6)));
+///
+/// // this will fail if digit1 fails
+/// assert_eq!(parser.parse("abc"), Err(Err::Error(("abc", ErrorKind::Digit))));
+/// # }
+/// ```
+pub fn map<I, O1, O2, E, F, G>(mut parser: F, mut f: G) -> impl FnMut(I) -> IResult<I, O2, E>
+where
+ F: Parser<I, O1, E>,
+ G: FnMut(O1) -> O2,
+{
+ move |input: I| {
+ let (input, o1) = parser.parse(input)?;
+ Ok((input, f(o1)))
+ }
+}
+
+/// Applies a function returning a `Result` over the result of a parser.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::character::complete::digit1;
+/// use nom::combinator::map_res;
+/// # fn main() {
+///
+/// let mut parse = map_res(digit1, |s: &str| s.parse::<u8>());
+///
+/// // the parser will convert the result of digit1 to a number
+/// assert_eq!(parse("123"), Ok(("", 123)));
+///
+/// // this will fail if digit1 fails
+/// assert_eq!(parse("abc"), Err(Err::Error(("abc", ErrorKind::Digit))));
+///
+/// // this will fail if the mapped function fails (a `u8` is too small to hold `123456`)
+/// assert_eq!(parse("123456"), Err(Err::Error(("123456", ErrorKind::MapRes))));
+/// # }
+/// ```
+pub fn map_res<I: Clone, O1, O2, E: FromExternalError<I, E2>, E2, F, G>(
+ mut parser: F,
+ mut f: G,
+) -> impl FnMut(I) -> IResult<I, O2, E>
+where
+ F: Parser<I, O1, E>,
+ G: FnMut(O1) -> Result<O2, E2>,
+{
+ move |input: I| {
+ let i = input.clone();
+ let (input, o1) = parser.parse(input)?;
+ match f(o1) {
+ Ok(o2) => Ok((input, o2)),
+ Err(e) => Err(Err::Error(E::from_external_error(i, ErrorKind::MapRes, e))),
+ }
+ }
+}
+
+/// Applies a function returning an `Option` over the result of a parser.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::character::complete::digit1;
+/// use nom::combinator::map_opt;
+/// # fn main() {
+///
+/// let mut parse = map_opt(digit1, |s: &str| s.parse::<u8>().ok());
+///
+/// // the parser will convert the result of digit1 to a number
+/// assert_eq!(parse("123"), Ok(("", 123)));
+///
+/// // this will fail if digit1 fails
+/// assert_eq!(parse("abc"), Err(Err::Error(("abc", ErrorKind::Digit))));
+///
+/// // this will fail if the mapped function fails (a `u8` is too small to hold `123456`)
+/// assert_eq!(parse("123456"), Err(Err::Error(("123456", ErrorKind::MapOpt))));
+/// # }
+/// ```
+pub fn map_opt<I: Clone, O1, O2, E: ParseError<I>, F, G>(
+ mut parser: F,
+ mut f: G,
+) -> impl FnMut(I) -> IResult<I, O2, E>
+where
+ F: Parser<I, O1, E>,
+ G: FnMut(O1) -> Option<O2>,
+{
+ move |input: I| {
+ let i = input.clone();
+ let (input, o1) = parser.parse(input)?;
+ match f(o1) {
+ Some(o2) => Ok((input, o2)),
+ None => Err(Err::Error(E::from_error_kind(i, ErrorKind::MapOpt))),
+ }
+ }
+}
+
+/// Applies a parser over the result of another one.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::character::complete::digit1;
+/// use nom::bytes::complete::take;
+/// use nom::combinator::map_parser;
+/// # fn main() {
+///
+/// let mut parse = map_parser(take(5u8), digit1);
+///
+/// assert_eq!(parse("12345"), Ok(("", "12345")));
+/// assert_eq!(parse("123ab"), Ok(("", "123")));
+/// assert_eq!(parse("123"), Err(Err::Error(("123", ErrorKind::Eof))));
+/// # }
+/// ```
+pub fn map_parser<I, O1, O2, E: ParseError<I>, F, G>(
+ mut parser: F,
+ mut applied_parser: G,
+) -> impl FnMut(I) -> IResult<I, O2, E>
+where
+ F: Parser<I, O1, E>,
+ G: Parser<O1, O2, E>,
+{
+ move |input: I| {
+ let (input, o1) = parser.parse(input)?;
+ let (_, o2) = applied_parser.parse(o1)?;
+ Ok((input, o2))
+ }
+}
+
+/// Creates a new parser from the output of the first parser, then apply that parser over the rest of the input.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::bytes::complete::take;
+/// use nom::number::complete::u8;
+/// use nom::combinator::flat_map;
+/// # fn main() {
+///
+/// let mut parse = flat_map(u8, take);
+///
+/// assert_eq!(parse(&[2, 0, 1, 2][..]), Ok((&[2][..], &[0, 1][..])));
+/// assert_eq!(parse(&[4, 0, 1, 2][..]), Err(Err::Error((&[0, 1, 2][..], ErrorKind::Eof))));
+/// # }
+/// ```
+pub fn flat_map<I, O1, O2, E: ParseError<I>, F, G, H>(
+ mut parser: F,
+ mut applied_parser: G,
+) -> impl FnMut(I) -> IResult<I, O2, E>
+where
+ F: Parser<I, O1, E>,
+ G: FnMut(O1) -> H,
+ H: Parser<I, O2, E>,
+{
+ move |input: I| {
+ let (input, o1) = parser.parse(input)?;
+ applied_parser(o1).parse(input)
+ }
+}
+
+/// Optional parser: Will return `None` if not successful.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::combinator::opt;
+/// use nom::character::complete::alpha1;
+/// # fn main() {
+///
+/// fn parser(i: &str) -> IResult<&str, Option<&str>> {
+/// opt(alpha1)(i)
+/// }
+///
+/// assert_eq!(parser("abcd;"), Ok((";", Some("abcd"))));
+/// assert_eq!(parser("123;"), Ok(("123;", None)));
+/// # }
+/// ```
+pub fn opt<I: Clone, O, E: ParseError<I>, F>(mut f: F) -> impl FnMut(I) -> IResult<I, Option<O>, E>
+where
+ F: Parser<I, O, E>,
+{
+ move |input: I| {
+ let i = input.clone();
+ match f.parse(input) {
+ Ok((i, o)) => Ok((i, Some(o))),
+ Err(Err::Error(_)) => Ok((i, None)),
+ Err(e) => Err(e),
+ }
+ }
+}
+
+/// Calls the parser if the condition is met.
+///
+/// ```rust
+/// # use nom::{Err, error::{Error, ErrorKind}, IResult};
+/// use nom::combinator::cond;
+/// use nom::character::complete::alpha1;
+/// # fn main() {
+///
+/// fn parser(b: bool, i: &str) -> IResult<&str, Option<&str>> {
+/// cond(b, alpha1)(i)
+/// }
+///
+/// assert_eq!(parser(true, "abcd;"), Ok((";", Some("abcd"))));
+/// assert_eq!(parser(false, "abcd;"), Ok(("abcd;", None)));
+/// assert_eq!(parser(true, "123;"), Err(Err::Error(Error::new("123;", ErrorKind::Alpha))));
+/// assert_eq!(parser(false, "123;"), Ok(("123;", None)));
+/// # }
+/// ```
+pub fn cond<I, O, E: ParseError<I>, F>(
+ b: bool,
+ mut f: F,
+) -> impl FnMut(I) -> IResult<I, Option<O>, E>
+where
+ F: Parser<I, O, E>,
+{
+ move |input: I| {
+ if b {
+ match f.parse(input) {
+ Ok((i, o)) => Ok((i, Some(o))),
+ Err(e) => Err(e),
+ }
+ } else {
+ Ok((input, None))
+ }
+ }
+}
+
+/// Tries to apply its parser without consuming the input.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::combinator::peek;
+/// use nom::character::complete::alpha1;
+/// # fn main() {
+///
+/// let mut parser = peek(alpha1);
+///
+/// assert_eq!(parser("abcd;"), Ok(("abcd;", "abcd")));
+/// assert_eq!(parser("123;"), Err(Err::Error(("123;", ErrorKind::Alpha))));
+/// # }
+/// ```
+pub fn peek<I: Clone, O, E: ParseError<I>, F>(mut f: F) -> impl FnMut(I) -> IResult<I, O, E>
+where
+ F: Parser<I, O, E>,
+{
+ move |input: I| {
+ let i = input.clone();
+ match f.parse(input) {
+ Ok((_, o)) => Ok((i, o)),
+ Err(e) => Err(e),
+ }
+ }
+}
+
+/// returns its input if it is at the end of input data
+///
+/// When we're at the end of the data, this combinator
+/// will succeed
+///
+/// ```
+/// # use std::str;
+/// # use nom::{Err, error::ErrorKind, IResult};
+/// # use nom::combinator::eof;
+///
+/// # fn main() {
+/// let parser = eof;
+/// assert_eq!(parser("abc"), Err(Err::Error(("abc", ErrorKind::Eof))));
+/// assert_eq!(parser(""), Ok(("", "")));
+/// # }
+/// ```
+pub fn eof<I: InputLength + Clone, E: ParseError<I>>(input: I) -> IResult<I, I, E> {
+ if input.input_len() == 0 {
+ let clone = input.clone();
+ Ok((input, clone))
+ } else {
+ Err(Err::Error(E::from_error_kind(input, ErrorKind::Eof)))
+ }
+}
+
+/// Transforms Incomplete into `Error`.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::bytes::streaming::take;
+/// use nom::combinator::complete;
+/// # fn main() {
+///
+/// let mut parser = complete(take(5u8));
+///
+/// assert_eq!(parser("abcdefg"), Ok(("fg", "abcde")));
+/// assert_eq!(parser("abcd"), Err(Err::Error(("abcd", ErrorKind::Complete))));
+/// # }
+/// ```
+pub fn complete<I: Clone, O, E: ParseError<I>, F>(mut f: F) -> impl FnMut(I) -> IResult<I, O, E>
+where
+ F: Parser<I, O, E>,
+{
+ move |input: I| {
+ let i = input.clone();
+ match f.parse(input) {
+ Err(Err::Incomplete(_)) => Err(Err::Error(E::from_error_kind(i, ErrorKind::Complete))),
+ rest => rest,
+ }
+ }
+}
+
+/// Succeeds if all the input has been consumed by its child parser.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::combinator::all_consuming;
+/// use nom::character::complete::alpha1;
+/// # fn main() {
+///
+/// let mut parser = all_consuming(alpha1);
+///
+/// assert_eq!(parser("abcd"), Ok(("", "abcd")));
+/// assert_eq!(parser("abcd;"),Err(Err::Error((";", ErrorKind::Eof))));
+/// assert_eq!(parser("123abcd;"),Err(Err::Error(("123abcd;", ErrorKind::Alpha))));
+/// # }
+/// ```
+pub fn all_consuming<I, O, E: ParseError<I>, F>(mut f: F) -> impl FnMut(I) -> IResult<I, O, E>
+where
+ I: InputLength,
+ F: Parser<I, O, E>,
+{
+ move |input: I| {
+ let (input, res) = f.parse(input)?;
+ if input.input_len() == 0 {
+ Ok((input, res))
+ } else {
+ Err(Err::Error(E::from_error_kind(input, ErrorKind::Eof)))
+ }
+ }
+}
+
+/// Returns the result of the child parser if it satisfies a verification function.
+///
+/// The verification function takes as argument a reference to the output of the
+/// parser.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::combinator::verify;
+/// use nom::character::complete::alpha1;
+/// # fn main() {
+///
+/// let mut parser = verify(alpha1, |s: &str| s.len() == 4);
+///
+/// assert_eq!(parser("abcd"), Ok(("", "abcd")));
+/// assert_eq!(parser("abcde"), Err(Err::Error(("abcde", ErrorKind::Verify))));
+/// assert_eq!(parser("123abcd;"),Err(Err::Error(("123abcd;", ErrorKind::Alpha))));
+/// # }
+/// ```
+pub fn verify<I: Clone, O1, O2, E: ParseError<I>, F, G>(
+ mut first: F,
+ second: G,
+) -> impl FnMut(I) -> IResult<I, O1, E>
+where
+ F: Parser<I, O1, E>,
+ G: Fn(&O2) -> bool,
+ O1: Borrow<O2>,
+ O2: ?Sized,
+{
+ move |input: I| {
+ let i = input.clone();
+ let (input, o) = first.parse(input)?;
+
+ if second(o.borrow()) {
+ Ok((input, o))
+ } else {
+ Err(Err::Error(E::from_error_kind(i, ErrorKind::Verify)))
+ }
+ }
+}
+
+/// Returns the provided value if the child parser succeeds.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::combinator::value;
+/// use nom::character::complete::alpha1;
+/// # fn main() {
+///
+/// let mut parser = value(1234, alpha1);
+///
+/// assert_eq!(parser("abcd"), Ok(("", 1234)));
+/// assert_eq!(parser("123abcd;"), Err(Err::Error(("123abcd;", ErrorKind::Alpha))));
+/// # }
+/// ```
+pub fn value<I, O1: Clone, O2, E: ParseError<I>, F>(
+ val: O1,
+ mut parser: F,
+) -> impl FnMut(I) -> IResult<I, O1, E>
+where
+ F: Parser<I, O2, E>,
+{
+ move |input: I| parser.parse(input).map(|(i, _)| (i, val.clone()))
+}
+
+/// Succeeds if the child parser returns an error.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::combinator::not;
+/// use nom::character::complete::alpha1;
+/// # fn main() {
+///
+/// let mut parser = not(alpha1);
+///
+/// assert_eq!(parser("123"), Ok(("123", ())));
+/// assert_eq!(parser("abcd"), Err(Err::Error(("abcd", ErrorKind::Not))));
+/// # }
+/// ```
+pub fn not<I: Clone, O, E: ParseError<I>, F>(mut parser: F) -> impl FnMut(I) -> IResult<I, (), E>
+where
+ F: Parser<I, O, E>,
+{
+ move |input: I| {
+ let i = input.clone();
+ match parser.parse(input) {
+ Ok(_) => Err(Err::Error(E::from_error_kind(i, ErrorKind::Not))),
+ Err(Err::Error(_)) => Ok((i, ())),
+ Err(e) => Err(e),
+ }
+ }
+}
+
+/// If the child parser was successful, return the consumed input as produced value.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::combinator::recognize;
+/// use nom::character::complete::{char, alpha1};
+/// use nom::sequence::separated_pair;
+/// # fn main() {
+///
+/// let mut parser = recognize(separated_pair(alpha1, char(','), alpha1));
+///
+/// assert_eq!(parser("abcd,efgh"), Ok(("", "abcd,efgh")));
+/// assert_eq!(parser("abcd;"),Err(Err::Error((";", ErrorKind::Char))));
+/// # }
+/// ```
+pub fn recognize<I: Clone + Offset + Slice<RangeTo<usize>>, O, E: ParseError<I>, F>(
+ mut parser: F,
+) -> impl FnMut(I) -> IResult<I, I, E>
+where
+ F: Parser<I, O, E>,
+{
+ move |input: I| {
+ let i = input.clone();
+ match parser.parse(i) {
+ Ok((i, _)) => {
+ let index = input.offset(&i);
+ Ok((i, input.slice(..index)))
+ }
+ Err(e) => Err(e),
+ }
+ }
+}
+
+/// if the child parser was successful, return the consumed input with the output
+/// as a tuple. Functions similarly to [recognize](fn.recognize.html) except it
+/// returns the parser output as well.
+///
+/// This can be useful especially in cases where the output is not the same type
+/// as the input, or the input is a user defined type.
+///
+/// Returned tuple is of the format `(consumed input, produced output)`.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::combinator::{consumed, value, recognize, map};
+/// use nom::character::complete::{char, alpha1};
+/// use nom::bytes::complete::tag;
+/// use nom::sequence::separated_pair;
+///
+/// fn inner_parser(input: &str) -> IResult<&str, bool> {
+/// value(true, tag("1234"))(input)
+/// }
+///
+/// # fn main() {
+///
+/// let mut consumed_parser = consumed(value(true, separated_pair(alpha1, char(','), alpha1)));
+///
+/// assert_eq!(consumed_parser("abcd,efgh1"), Ok(("1", ("abcd,efgh", true))));
+/// assert_eq!(consumed_parser("abcd;"),Err(Err::Error((";", ErrorKind::Char))));
+///
+///
+/// // the first output (representing the consumed input)
+/// // should be the same as that of the `recognize` parser.
+/// let mut recognize_parser = recognize(inner_parser);
+/// let mut consumed_parser = map(consumed(inner_parser), |(consumed, output)| consumed);
+///
+/// assert_eq!(recognize_parser("1234"), consumed_parser("1234"));
+/// assert_eq!(recognize_parser("abcd"), consumed_parser("abcd"));
+/// # }
+/// ```
+pub fn consumed<I, O, F, E>(mut parser: F) -> impl FnMut(I) -> IResult<I, (I, O), E>
+where
+ I: Clone + Offset + Slice<RangeTo<usize>>,
+ E: ParseError<I>,
+ F: Parser<I, O, E>,
+{
+ move |input: I| {
+ let i = input.clone();
+ match parser.parse(i) {
+ Ok((remaining, result)) => {
+ let index = input.offset(&remaining);
+ let consumed = input.slice(..index);
+ Ok((remaining, (consumed, result)))
+ }
+ Err(e) => Err(e),
+ }
+ }
+}
+
+/// transforms an error to failure
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::combinator::cut;
+/// use nom::character::complete::alpha1;
+/// # fn main() {
+///
+/// let mut parser = cut(alpha1);
+///
+/// assert_eq!(parser("abcd;"), Ok((";", "abcd")));
+/// assert_eq!(parser("123;"), Err(Err::Failure(("123;", ErrorKind::Alpha))));
+/// # }
+/// ```
+pub fn cut<I, O, E: ParseError<I>, F>(mut parser: F) -> impl FnMut(I) -> IResult<I, O, E>
+where
+ F: Parser<I, O, E>,
+{
+ move |input: I| match parser.parse(input) {
+ Err(Err::Error(e)) => Err(Err::Failure(e)),
+ rest => rest,
+ }
+}
+
+/// automatically converts the child parser's result to another type
+///
+/// it will be able to convert the output value and the error value
+/// as long as the `Into` implementations are available
+///
+/// ```rust
+/// # use nom::IResult;
+/// use nom::combinator::into;
+/// use nom::character::complete::alpha1;
+/// # fn main() {
+///
+/// fn parser1(i: &str) -> IResult<&str, &str> {
+/// alpha1(i)
+/// }
+///
+/// let mut parser2 = into(parser1);
+///
+/// // the parser converts the &str output of the child parser into a Vec<u8>
+/// let bytes: IResult<&str, Vec<u8>> = parser2("abcd");
+/// assert_eq!(bytes, Ok(("", vec![97, 98, 99, 100])));
+/// # }
+/// ```
+pub fn into<I, O1, O2, E1, E2, F>(mut parser: F) -> impl FnMut(I) -> IResult<I, O2, E2>
+where
+ O1: Into<O2>,
+ E1: Into<E2>,
+ E1: ParseError<I>,
+ E2: ParseError<I>,
+ F: Parser<I, O1, E1>,
+{
+ //map(parser, Into::into)
+ move |input: I| match parser.parse(input) {
+ Ok((i, o)) => Ok((i, o.into())),
+ Err(Err::Error(e)) => Err(Err::Error(e.into())),
+ Err(Err::Failure(e)) => Err(Err::Failure(e.into())),
+ Err(Err::Incomplete(e)) => Err(Err::Incomplete(e)),
+ }
+}
+
+/// Creates an iterator from input data and a parser.
+///
+/// Call the iterator's [ParserIterator::finish] method to get the remaining input if successful,
+/// or the error value if we encountered an error.
+///
+/// ```rust
+/// use nom::{combinator::iterator, IResult, bytes::complete::tag, character::complete::alpha1, sequence::terminated};
+/// use std::collections::HashMap;
+///
+/// let data = "abc|defg|hijkl|mnopqr|123";
+/// let mut it = iterator(data, terminated(alpha1, tag("|")));
+///
+/// let parsed = it.map(|v| (v, v.len())).collect::<HashMap<_,_>>();
+/// let res: IResult<_,_> = it.finish();
+///
+/// assert_eq!(parsed, [("abc", 3usize), ("defg", 4), ("hijkl", 5), ("mnopqr", 6)].iter().cloned().collect());
+/// assert_eq!(res, Ok(("123", ())));
+/// ```
+pub fn iterator<Input, Output, Error, F>(input: Input, f: F) -> ParserIterator<Input, Error, F>
+where
+ F: Parser<Input, Output, Error>,
+ Error: ParseError<Input>,
+{
+ ParserIterator {
+ iterator: f,
+ input,
+ state: Some(State::Running),
+ }
+}
+
+/// Main structure associated to the [iterator] function.
+pub struct ParserIterator<I, E, F> {
+ iterator: F,
+ input: I,
+ state: Option<State<E>>,
+}
+
+impl<I: Clone, E, F> ParserIterator<I, E, F> {
+ /// Returns the remaining input if parsing was successful, or the error if we encountered an error.
+ pub fn finish(mut self) -> IResult<I, (), E> {
+ match self.state.take().unwrap() {
+ State::Running | State::Done => Ok((self.input, ())),
+ State::Failure(e) => Err(Err::Failure(e)),
+ State::Incomplete(i) => Err(Err::Incomplete(i)),
+ }
+ }
+}
+
+impl<'a, Input, Output, Error, F> core::iter::Iterator for &'a mut ParserIterator<Input, Error, F>
+where
+ F: FnMut(Input) -> IResult<Input, Output, Error>,
+ Input: Clone,
+{
+ type Item = Output;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ if let State::Running = self.state.take().unwrap() {
+ let input = self.input.clone();
+
+ match (self.iterator)(input) {
+ Ok((i, o)) => {
+ self.input = i;
+ self.state = Some(State::Running);
+ Some(o)
+ }
+ Err(Err::Error(_)) => {
+ self.state = Some(State::Done);
+ None
+ }
+ Err(Err::Failure(e)) => {
+ self.state = Some(State::Failure(e));
+ None
+ }
+ Err(Err::Incomplete(i)) => {
+ self.state = Some(State::Incomplete(i));
+ None
+ }
+ }
+ } else {
+ None
+ }
+ }
+}
+
+enum State<E> {
+ Running,
+ Done,
+ Failure(E),
+ Incomplete(Needed),
+}
+
+/// a parser which always succeeds with given value without consuming any input.
+///
+/// It can be used for example as the last alternative in `alt` to
+/// specify the default case.
+///
+/// ```rust
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::branch::alt;
+/// use nom::combinator::{success, value};
+/// use nom::character::complete::char;
+/// # fn main() {
+///
+/// let mut parser = success::<_,_,(_,ErrorKind)>(10);
+/// assert_eq!(parser("xyz"), Ok(("xyz", 10)));
+///
+/// let mut sign = alt((value(-1, char('-')), value(1, char('+')), success::<_,_,(_,ErrorKind)>(1)));
+/// assert_eq!(sign("+10"), Ok(("10", 1)));
+/// assert_eq!(sign("-10"), Ok(("10", -1)));
+/// assert_eq!(sign("10"), Ok(("10", 1)));
+/// # }
+/// ```
+pub fn success<I, O: Clone, E: ParseError<I>>(val: O) -> impl Fn(I) -> IResult<I, O, E> {
+ move |input: I| Ok((input, val.clone()))
+}
+
+/// A parser which always fails.
+///
+/// ```rust
+/// # use nom::{Err, error::ErrorKind, IResult};
+/// use nom::combinator::fail;
+///
+/// let s = "string";
+/// assert_eq!(fail::<_, &str, _>(s), Err(Err::Error((s, ErrorKind::Fail))));
+/// ```
+pub fn fail<I, O, E: ParseError<I>>(i: I) -> IResult<I, O, E> {
+ Err(Err::Error(E::from_error_kind(i, ErrorKind::Fail)))
+}
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-03 17:51:41 +0000