Trait ParserExt

pub trait ParserExt: Parser + Sized {
    // Provided methods
    fn with<P2>(self, p: P2) -> With<Self, P2>
       where P2: Parser<Input = Self::Input> { ... }
    fn skip<P2>(self, p: P2) -> Skip<Self, P2>
       where P2: Parser<Input = Self::Input> { ... }
    fn and<P2>(self, p: P2) -> And<Self, P2>
       where P2: Parser<Input = Self::Input> { ... }
    fn or<P2>(self, p: P2) -> Or<Self, P2>
       where P2: Parser<Input = Self::Input> { ... }
    fn then<N, F>(self, f: F) -> Then<Self, F>
       where F: FnMut(Self::Output) -> N,
             N: Parser<Input = Self::Input> { ... }
    fn map<F, B>(self, f: F) -> Map<Self, F>
       where F: FnMut(Self::Output) -> B { ... }
    fn message<S>(self, msg: S) -> Message<Self>
       where S: Into<Info<<Self::Input as Stream>::Item>> { ... }
    fn expected<S>(self, msg: S) -> Expected<Self>
       where S: Into<Info<<Self::Input as Stream>::Item>> { ... }
    fn and_then<F, O, E>(self, f: F) -> AndThen<Self, F>
       where F: FnMut(Self::Output) -> Result<O, E>,
             E: Into<Error<<Self::Input as Stream>::Item>> { ... }
    fn iter(self, input: State<Self::Input>) -> Iter<Self>  { ... }
}

Extension trait which provides functions that are more conveniently used through method calls

Provided Methods

fn with<P2>(self, p: P2) -> With<Self, P2>

where P2: Parser<Input = Self::Input>,

Discards the value of the self parser and returns the value of p Fails if any of the parsers fails

let result = digit()
    .with(token('i'))
    .parse("9i")
    .map(|x| x.0);
assert_eq!(result, Ok('i'));

fn skip<P2>(self, p: P2) -> Skip<Self, P2>

where P2: Parser<Input = Self::Input>,

Discards the value of the p parser and returns the value of self Fails if any of the parsers fails

let result = digit()
    .skip(token('i'))
    .parse("9i")
    .map(|x| x.0);
assert_eq!(result, Ok('9'));

fn and<P2>(self, p: P2) -> And<Self, P2>

where P2: Parser<Input = Self::Input>,

Parses with self followed by p Succeds if both parsers succed, otherwise fails Returns a tuple with both values on success

let result = digit()
    .and(token('i'))
    .parse("9i")
    .map(|x| x.0);
assert_eq!(result, Ok(('9', 'i')));

fn or<P2>(self, p: P2) -> Or<Self, P2>

where P2: Parser<Input = Self::Input>,

Tries to parse using self and if it fails returns the result of parsing p

let result = digit().map(|_| "")
    .or(string("let"))
    .parse("let")
    .map(|x| x.0);
assert_eq!(result, Ok("let"));

fn then<N, F>(self, f: F) -> Then<Self, F>

where F: FnMut(Self::Output) -> N, N: Parser<Input = Self::Input>,

Parses using self and then passes the value to f which returns a parser used to parse the rest of the input

let result = digit()
    .then(|d| parser(move |input| {
        if d == '9' {
            Ok((9, Consumed::Empty(input)))
        }
        else {
            let err = ParseError::new(input.position, Error::Message("Not a nine".into()));
            Err((Consumed::Empty(err)))
        }
    }))
    .parse("9");
assert_eq!(result, Ok((9, "")));

fn map<F, B>(self, f: F) -> Map<Self, F>

where F: FnMut(Self::Output) -> B,

Uses f to map over the parsed value

let result = digit()
    .map(|c| c == '9')
    .parse("9")
    .map(|x| x.0);
assert_eq!(result, Ok(true));

fn message<S>(self, msg: S) -> Message<Self>

where S: Into<Info<<Self::Input as Stream>::Item>>,

Parses with self and if it fails, adds the message msg to the error

let result = token('9')
    .message("Not a nine")
    .parse("8");
assert!(result.is_err());
assert!(result.unwrap_err().errors.iter()
    .find(|e| **e == Error::Message("Not a nine".into())).is_some());

fn expected<S>(self, msg: S) -> Expected<Self>

where S: Into<Info<<Self::Input as Stream>::Item>>,

Parses with self and if it fails without consuming any input any expected errors are replaced by msg. msg is then used in error messages as “Expected msg”.

let result = token('9')
    .expected("9")
    .parse("8");
assert!(result.is_err());
assert!(result.unwrap_err().errors.iter()
    .find(|e| **e == Error::Expected("9".into())).is_some());

fn and_then<F, O, E>(self, f: F) -> AndThen<Self, F>

where F: FnMut(Self::Output) -> Result<O, E>, E: Into<Error<<Self::Input as Stream>::Item>>,

Parses with self and applies f on the result if self parses successfully f may optionally fail with an error which is automatically converted to a ParseError

let mut parser = many1(digit())
    .and_then(|s: String| s.parse::<i32>());
let result = parser.parse("1234");
assert_eq!(result, Ok((1234, "")));
let err = parser.parse("abc");
assert!(err.is_err());

fn iter(self, input: State<Self::Input>) -> Iter<Self>

Creates an iterator from a parser and a state. Can be used as an alternative to many when collecting directly into a FromIterator type is not desirable

let mut buffer = String::new();
let number = parser(|input| {
    buffer.clear();
    let mut iter = digit().iter(input);
    buffer.extend(&mut iter);
    let i = buffer.parse::<i32>().unwrap();
    iter.into_result(i)
});
let result = sep_by(number, char(','))
    .parse("123,45,6");
assert_eq!(result, Ok((vec![123, 45, 6], "")));

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<P: Parser> ParserExt for P