| //! 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))) |
| } |