Struct Lexer 

pub struct Lexer<'source, Token: Logos<'source>> {
    pub extras: Token::Extras,
    /* private fields */
}

Lexer is the main struct of the crate that allows you to read through a Source and produce tokens for enums implementing the Logos trait.

Fields

extras: Token::Extras

Extras associated with the Token.

Implementations

impl<'source, Token: Logos<'source>> Lexer<'source, Token>

pub fn new(source: &'source Token::Source) -> Self

where Token::Extras: Default,

Create a new Lexer.

Due to type inference, it might be more ergonomic to construct it by calling Token::lexer on any Token with derived Logos.

pub fn with_extras( source: &'source Token::Source, extras: Token::Extras, ) -> Self

Create a new Lexer with the provided Extras.

Due to type inference, it might be more ergonomic to construct it by calling Token::lexer_with_extras on any Token with derived Logos.

pub fn source(&self) -> &'source Token::Source

Source from which this Lexer is reading tokens.

pub fn spanned(self) -> SpannedIter<'source, Token>

Wrap the Lexer in an Iterator that produces tuples of (Token, Span).

Example

use logos::Logos;

#[derive(Debug, PartialEq, Clone, Default)]
enum LexingError {
    NumberParseError,
    #[default]
    Other
}

impl From<std::num::ParseIntError> for LexingError {
   fn from(_: std::num::ParseIntError) -> Self {
      LexingError::NumberParseError
  }
}

impl From<std::num::ParseFloatError> for LexingError {
  fn from(_: std::num::ParseFloatError) -> Self {
     LexingError::NumberParseError
  }
}

#[derive(Logos, Debug, PartialEq)]
#[logos(error = LexingError)]
enum Example {
    #[regex(r"[ \n\t\f]+", logos::skip)]
    Ignored,

    #[regex("-?[0-9]+", |lex| lex.slice().parse())]
    Integer(i64),

    #[regex("-?[0-9]+\\.[0-9]+", |lex| lex.slice().parse())]
    Float(f64),
}

let tokens: Vec<_> = Example::lexer("42 3.14 -5 f").spanned().collect();

assert_eq!(
    tokens,
    &[
        (Ok(Example::Integer(42)), 0..2),
        (Ok(Example::Float(3.14)), 3..7),
        (Ok(Example::Integer(-5)), 8..10),
        (Err(LexingError::Other), 11..12), // 'f' is not a recognized token
    ],
);

Examples found in repository

examples/calculator.rs (line 144)

fn main() {
    //reads the input expression from the command line
    let input = env::args()
        .nth(1)
        .expect("Expected expression argument (e.g. `1 + 7 * (3 - 4) / 5`)");

    //creates a lexer instance from the input
    let lexer = Token::lexer(&input);

    //splits the input into tokens, using the lexer
    let mut tokens = vec![];
    for (token, span) in lexer.spanned() {
        match token {
            Ok(token) => tokens.push(token),
            Err(e) => {
                println!("lexer error at {:?}: {}", span, e);
                return;
            }
        }
    }

    //parses the tokens to construct an AST
    let ast = match parser().parse(&tokens).into_result() {
        Ok(expr) => {
            println!("[AST]\n{:#?}", expr);
            expr
        }
        Err(e) => {
            println!("parse error: {:#?}", e);
            return;
        }
    };

    //evaluates the AST to get the result
    println!("\n[result]\n{}", ast.eval());
}

pub fn span(&self) -> Span

Get the range for the current token in Source.

Examples found in repository

examples/extras.rs (line 35)

fn newline_callback(lex: &mut Lexer<Token>) -> Skip {
    lex.extras.0 += 1;
    lex.extras.1 = lex.span().end;
    Skip
}

/// Compute the line and column position for the current word.
fn word_callback(lex: &mut Lexer<Token>) -> (usize, usize) {
    let line = lex.extras.0;
    let column = lex.span().start - lex.extras.1;

    (line, column)
}

examples/json.rs (line 100)

fn parse_value(lexer: &mut Lexer<'_, Token>) -> Result<Value> {
    if let Some(token) = lexer.next() {
        match token {
            Ok(Token::Bool(b)) => Ok(Value::Bool(b)),
            Ok(Token::BraceOpen) => parse_object(lexer),
            Ok(Token::BracketOpen) => parse_array(lexer),
            Ok(Token::Null) => Ok(Value::Null),
            Ok(Token::Number(n)) => Ok(Value::Number(n)),
            Ok(Token::String(s)) => Ok(Value::String(s)),
            _ => Err((
                "unexpected token here (context: value)".to_owned(),
                lexer.span(),
            )),
        }
    } else {
        Err(("empty values are not allowed".to_owned(), lexer.span()))
    }
}
/* ANCHOR_END: value */

/* ANCHOR: array */
/// Parse a token stream into an array and return when
/// a valid terminator is found.
///
/// > NOTE: we assume '[' was consumed.
fn parse_array(lexer: &mut Lexer<'_, Token>) -> Result<Value> {
    let mut array = Vec::new();
    let span = lexer.span();
    let mut awaits_comma = false;
    let mut awaits_value = false;

    while let Some(token) = lexer.next() {
        match token {
            Ok(Token::Bool(b)) if !awaits_comma => {
                array.push(Value::Bool(b));
                awaits_value = false;
            }
            Ok(Token::BraceOpen) if !awaits_comma => {
                let object = parse_object(lexer)?;
                array.push(object);
                awaits_value = false;
            }
            Ok(Token::BracketOpen) if !awaits_comma => {
                let sub_array = parse_array(lexer)?;
                array.push(sub_array);
                awaits_value = false;
            }
            Ok(Token::BracketClose) if !awaits_value => return Ok(Value::Array(array)),
            Ok(Token::Comma) if awaits_comma => awaits_value = true,
            Ok(Token::Null) if !awaits_comma => {
                array.push(Value::Null);
                awaits_value = false
            }
            Ok(Token::Number(n)) if !awaits_comma => {
                array.push(Value::Number(n));
                awaits_value = false;
            }
            Ok(Token::String(s)) if !awaits_comma => {
                array.push(Value::String(s));
                awaits_value = false;
            }
            _ => {
                return Err((
                    "unexpected token here (context: array)".to_owned(),
                    lexer.span(),
                ))
            }
        }
        awaits_comma = !awaits_value;
    }
    Err(("unmatched opening bracket defined here".to_owned(), span))
}
/* ANCHOR_END: array */

/* ANCHOR: object */
/// Parse a token stream into an object and return when
/// a valid terminator is found.
///
/// > NOTE: we assume '{' was consumed.
fn parse_object(lexer: &mut Lexer<'_, Token>) -> Result<Value> {
    let mut map = HashMap::new();
    let span = lexer.span();
    let mut awaits_comma = false;
    let mut awaits_key = false;

    while let Some(token) = lexer.next() {
        match token {
            Ok(Token::BraceClose) if !awaits_key => return Ok(Value::Object(map)),
            Ok(Token::Comma) if awaits_comma => awaits_key = true,
            Ok(Token::String(key)) if !awaits_comma => {
                match lexer.next() {
                    Some(Ok(Token::Colon)) => (),
                    _ => {
                        return Err((
                            "unexpected token here, expecting ':'".to_owned(),
                            lexer.span(),
                        ))
                    }
                }
                let value = parse_value(lexer)?;
                map.insert(key, value);
                awaits_key = false;
            }
            _ => {
                return Err((
                    "unexpected token here (context: object)".to_owned(),
                    lexer.span(),
                ))
            }
        }
        awaits_comma = !awaits_key;
    }
    Err(("unmatched opening brace defined here".to_owned(), span))
}

examples/json_borrowed.rs (line 96)

fn parse_value<'source>(lexer: &mut Lexer<'source, Token<'source>>) -> Result<Value<'source>> {
    if let Some(token) = lexer.next() {
        match token {
            Ok(Token::Bool(b)) => Ok(Value::Bool(b)),
            Ok(Token::BraceOpen) => parse_object(lexer),
            Ok(Token::BracketOpen) => parse_array(lexer),
            Ok(Token::Null) => Ok(Value::Null),
            Ok(Token::Number(n)) => Ok(Value::Number(n)),
            Ok(Token::String(s)) => Ok(Value::String(s)),
            _ => Err((
                "unexpected token here (context: value)".to_owned(),
                lexer.span(),
            )),
        }
    } else {
        Err(("empty values are not allowed".to_owned(), lexer.span()))
    }
}
/* ANCHOR_END: value */

/* ANCHOR: array */
/// Parse a token stream into an array and return when
/// a valid terminator is found.
///
/// > NOTE: we assume '[' was consumed.
fn parse_array<'source>(lexer: &mut Lexer<'source, Token<'source>>) -> Result<Value<'source>> {
    let mut array = Vec::new();
    let span = lexer.span();
    let mut awaits_comma = false;
    let mut awaits_value = false;

    while let Some(token) = lexer.next() {
        match token {
            Ok(Token::Bool(b)) if !awaits_comma => {
                array.push(Value::Bool(b));
                awaits_value = false;
            }
            Ok(Token::BraceOpen) if !awaits_comma => {
                let object = parse_object(lexer)?;
                array.push(object);
                awaits_value = false;
            }
            Ok(Token::BracketOpen) if !awaits_comma => {
                let sub_array = parse_array(lexer)?;
                array.push(sub_array);
                awaits_value = false;
            }
            Ok(Token::BracketClose) if !awaits_value => return Ok(Value::Array(array)),
            Ok(Token::Comma) if awaits_comma => awaits_value = true,
            Ok(Token::Null) if !awaits_comma => {
                array.push(Value::Null);
                awaits_value = false
            }
            Ok(Token::Number(n)) if !awaits_comma => {
                array.push(Value::Number(n));
                awaits_value = false;
            }
            Ok(Token::String(s)) if !awaits_comma => {
                array.push(Value::String(s));
                awaits_value = false;
            }
            _ => {
                return Err((
                    "unexpected token here (context: array)".to_owned(),
                    lexer.span(),
                ))
            }
        }
        awaits_comma = !awaits_value;
    }
    Err(("unmatched opening bracket defined here".to_owned(), span))
}
/* ANCHOR_END: array */

/* ANCHOR: object */
/// Parse a token stream into an object and return when
/// a valid terminator is found.
///
/// > NOTE: we assume '{' was consumed.
fn parse_object<'source>(lexer: &mut Lexer<'source, Token<'source>>) -> Result<Value<'source>> {
    let mut map = HashMap::new();
    let span = lexer.span();
    let mut awaits_comma = false;
    let mut awaits_key = false;

    while let Some(token) = lexer.next() {
        match token {
            Ok(Token::BraceClose) if !awaits_key => return Ok(Value::Object(map)),
            Ok(Token::Comma) if awaits_comma => awaits_key = true,
            Ok(Token::String(key)) if !awaits_comma => {
                match lexer.next() {
                    Some(Ok(Token::Colon)) => (),
                    _ => {
                        return Err((
                            "unexpected token here, expecting ':'".to_owned(),
                            lexer.span(),
                        ))
                    }
                }
                let value = parse_value(lexer)?;
                map.insert(key, value);
                awaits_key = false;
            }
            _ => {
                return Err((
                    "unexpected token here (context: object)".to_owned(),
                    lexer.span(),
                ))
            }
        }
        awaits_comma = !awaits_key;
    }
    Err(("unmatched opening brace defined here".to_owned(), span))
}

pub fn slice(&self) -> <Token::Source as Source>::Slice<'source>

Get a string slice of the current token.

Examples found in repository

examples/custom_error.rs (line 35)

    fn from_lexer(lex: &mut logos::Lexer<'_, Token>) -> Self {
        LexingError::NonAsciiCharacter(lex.slice().chars().next().unwrap())
    }
}

#[derive(Debug, Logos, PartialEq)]
#[logos(error(LexingError, LexingError::from_lexer))]
#[logos(skip r"[ \t]+")]
enum Token {
    #[regex(r"[a-zA-Z]+")]
    Word,
    #[regex(r"[0-9]+", |lex| lex.slice().parse())]
    Integer(u8),
}

fn main() {
    // 256 overflows u8, since u8's max value is 255.
    // 'é' is not a valid ascii letter.
    let mut lex = Token::lexer("Hello 256 Jérome");

    assert_eq!(lex.next(), Some(Ok(Token::Word)));
    assert_eq!(lex.slice(), "Hello");

    assert_eq!(
        lex.next(),
        Some(Err(LexingError::InvalidInteger(
            "overflow error".to_owned()
        )))
    );
    assert_eq!(lex.slice(), "256");

    assert_eq!(lex.next(), Some(Ok(Token::Word)));
    assert_eq!(lex.slice(), "J");

    assert_eq!(lex.next(), Some(Err(LexingError::NonAsciiCharacter('é'))));
    assert_eq!(lex.slice(), "é");

    assert_eq!(lex.next(), Some(Ok(Token::Word)));
    assert_eq!(lex.slice(), "rome");

    assert_eq!(lex.next(), None);
}

examples/extras.rs (line 67)

fn main() {
    let src = fs::read_to_string(env::args().nth(1).expect("Expected file argument"))
        .expect("Failed to read file");

    let mut lex = Token::lexer(src.as_str());

    while let Some(token) = lex.next() {
        if let Ok(Token::Word((line, column))) = token {
            println!("Word '{}' found at ({}, {})", lex.slice(), line, column);
        }
    }
}

examples/string-interpolation.rs (line 52)

fn get_string_content(lex: &mut Lexer<StringContext>) -> String {
    let mut s = String::new();
    while let Some(Ok(token)) = lex.next() {
        match token {
            StringContext::Content => s.push_str(lex.slice()),
            StringContext::DollarSign => s.push('$'),
            StringContext::InterpolationStart(value) => s.push_str(&value),
            StringContext::Quote => break,
        }
    }
    s
}

fn variable_definition(lex: &mut Lexer<VariableDefinitionContext>) -> Option<(String, String)> {
    let id = lex.slice().to_string();
    if let Some(Ok(VariableDefinitionContext::Equals)) = lex.next() {
        if let Some(Ok(VariableDefinitionContext::Quote)) = lex.next() {
            let mut lex2 = lex.clone().morph::<StringContext>();
            let value = get_string_content(&mut lex2);
            *lex = lex2.morph();
            lex.extras.insert(id.clone(), value.clone());
            return Some((id, value));
        }
    }
    None
}
/* ANCHOR_END: variable_definition */

/* ANCHOR: evaluate_interpolation */
fn evaluate_interpolation(lex: &mut Lexer<StringContext>) -> Option<String> {
    let mut lex2 = lex.clone().morph::<StringInterpolationContext>();
    let mut interpolation = String::new();
    while let Some(result) = lex2.next() {
        match result {
            Ok(token) => match token {
                StringInterpolationContext::Id(value) => interpolation.push_str(&value),
                StringInterpolationContext::Quote => {
                    *lex = lex2.morph();
                    interpolation.push_str(&get_string_content(lex));
                    lex2 = lex.clone().morph();
                }
                StringInterpolationContext::InterpolationEnd => break,
            },
            Err(()) => panic!("Interpolation error"),
        }
    }
    *lex = lex2.morph();
    Some(interpolation)
}
/* ANCHOR_END: evaluate_interpolation */

/* ANCHOR: get_variable_value */
fn get_variable_value(lex: &mut Lexer<StringInterpolationContext>) -> Option<String> {
    if let Some(value) = lex.extras.get(lex.slice()) {
        return Some(value.clone());
    }
    None
}

pub fn remainder(&self) -> <Token::Source as Source>::Slice<'source>

Get a slice of remaining source, starting at the end of current token.

pub fn morph<Token2>(self) -> Lexer<'source, Token2>

where Token2: Logos<'source, Source = Token::Source>, Token::Extras: Into<Token2::Extras>,

Turn this lexer into a lexer for a new token type.

The new lexer continues to point at the same span as the current lexer, and the current token becomes the error token of the new token type.

Examples found in repository

examples/string-interpolation.rs (line 65)

fn variable_definition(lex: &mut Lexer<VariableDefinitionContext>) -> Option<(String, String)> {
    let id = lex.slice().to_string();
    if let Some(Ok(VariableDefinitionContext::Equals)) = lex.next() {
        if let Some(Ok(VariableDefinitionContext::Quote)) = lex.next() {
            let mut lex2 = lex.clone().morph::<StringContext>();
            let value = get_string_content(&mut lex2);
            *lex = lex2.morph();
            lex.extras.insert(id.clone(), value.clone());
            return Some((id, value));
        }
    }
    None
}
/* ANCHOR_END: variable_definition */

/* ANCHOR: evaluate_interpolation */
fn evaluate_interpolation(lex: &mut Lexer<StringContext>) -> Option<String> {
    let mut lex2 = lex.clone().morph::<StringInterpolationContext>();
    let mut interpolation = String::new();
    while let Some(result) = lex2.next() {
        match result {
            Ok(token) => match token {
                StringInterpolationContext::Id(value) => interpolation.push_str(&value),
                StringInterpolationContext::Quote => {
                    *lex = lex2.morph();
                    interpolation.push_str(&get_string_content(lex));
                    lex2 = lex.clone().morph();
                }
                StringInterpolationContext::InterpolationEnd => break,
            },
            Err(()) => panic!("Interpolation error"),
        }
    }
    *lex = lex2.morph();
    Some(interpolation)
}

pub fn bump(&mut self, n: usize)

Bumps the end of currently lexed token by n bytes.

Panics

Panics if adding n to current offset would place the Lexer beyond the last byte, or in the middle of an UTF-8 code point (does not apply when lexing raw &[u8]).

Trait Implementations

impl<'source, Token> Clone for Lexer<'source, Token>

where Token: Logos<'source> + Clone, Token::Extras: Clone,

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'source, Token> Debug for Lexer<'source, Token>

where Token: Logos<'source>, Token::Source: Debug, Token::Extras: Debug,

fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'source, Token> Iterator for Lexer<'source, Token>

where Token: Logos<'source>,

type Item = Result<Token, <Token as Logos<'source>>::Error>

The type of the elements being iterated over.

fn next(&mut self) -> Option<Result<Token, Token::Error>>

Advances the iterator and returns the next value.

fn next_chunk<const N: usize>( &mut self, ) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>

where Self: Sized,

🔬This is a nightly-only experimental API. (iter_next_chunk)

Advances the iterator and returns an array containing the next N values.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator.

fn count(self) -> usize

where Self: Sized,

Consumes the iterator, counting the number of iterations and returning it.

fn last(self) -> Option<Self::Item>

where Self: Sized,

Consumes the iterator, returning the last element.

fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

🔬This is a nightly-only experimental API. (iter_advance_by)

Advances the iterator by n elements.

fn nth(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element of the iterator.

fn step_by(self, step: usize) -> StepBy<Self>

where Self: Sized,

Creates an iterator starting at the same point, but stepping by the given amount at each iteration.

fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>

where Self: Sized, U: IntoIterator<Item = Self::Item>,

Takes two iterators and creates a new iterator over both in sequence.

fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>

where Self: Sized, U: IntoIterator,

‘Zips up’ two iterators into a single iterator of pairs.

fn intersperse(self, separator: Self::Item) -> Intersperse<Self>

where Self: Sized, Self::Item: Clone,

🔬This is a nightly-only experimental API. (iter_intersperse)

Creates a new iterator which places a copy of separator between adjacent items of the original iterator.

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>

where Self: Sized, G: FnMut() -> Self::Item,

🔬This is a nightly-only experimental API. (iter_intersperse)

Creates a new iterator which places an item generated by separator between adjacent items of the original iterator.

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

where Self: Sized, F: FnMut(Self::Item) -> B,

Takes a closure and creates an iterator which calls that closure on each element.

fn for_each<F>(self, f: F)

where Self: Sized, F: FnMut(Self::Item),

Calls a closure on each element of an iterator.

fn filter<P>(self, predicate: P) -> Filter<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator which uses a closure to determine if an element should be yielded.

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>

where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both filters and maps.

fn enumerate(self) -> Enumerate<Self>

where Self: Sized,

Creates an iterator which gives the current iteration count as well as the next value.

fn peekable(self) -> Peekable<Self>

where Self: Sized,

Creates an iterator which can use the peek and peek_mut methods to look at the next element of the iterator without consuming it. See their documentation for more information.

fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that skips elements based on a predicate.

fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that yields elements based on a predicate.

fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>

where Self: Sized, P: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both yields elements based on a predicate and maps.

fn skip(self, n: usize) -> Skip<Self>

where Self: Sized,

Creates an iterator that skips the first n elements.

fn take(self, n: usize) -> Take<Self>

where Self: Sized,

Creates an iterator that yields the first n elements, or fewer if the underlying iterator ends sooner.

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>

where Self: Sized, F: FnMut(&mut St, Self::Item) -> Option<B>,

An iterator adapter which, like fold, holds internal state, but unlike fold, produces a new iterator.

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>

where Self: Sized, U: IntoIterator, F: FnMut(Self::Item) -> U,

Creates an iterator that works like map, but flattens nested structure.

fn flatten(self) -> Flatten<Self>

where Self: Sized, Self::Item: IntoIterator,

Creates an iterator that flattens nested structure.

fn map_windows<F, R, const N: usize>(self, f: F) -> MapWindows<Self, F, N>

where Self: Sized, F: FnMut(&[Self::Item; N]) -> R,

🔬This is a nightly-only experimental API. (iter_map_windows)

Calls the given function f for each contiguous window of size N over self and returns an iterator over the outputs of f. Like slice::windows(), the windows during mapping overlap as well.

fn fuse(self) -> Fuse<Self>

where Self: Sized,

Creates an iterator which ends after the first None.

fn inspect<F>(self, f: F) -> Inspect<Self, F>

where Self: Sized, F: FnMut(&Self::Item),

Does something with each element of an iterator, passing the value on.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Iterator.

fn collect<B>(self) -> B

where B: FromIterator<Self::Item>, Self: Sized,

Transforms an iterator into a collection.

fn try_collect<B>( &mut self, ) -> <<Self::Item as Try>::Residual as Residual<B>>::TryType

where Self: Sized, Self::Item: Try, <Self::Item as Try>::Residual: Residual<B>, B: FromIterator<<Self::Item as Try>::Output>,

🔬This is a nightly-only experimental API. (iterator_try_collect)

Fallibly transforms an iterator into a collection, short circuiting if a failure is encountered.

fn collect_into<E>(self, collection: &mut E) -> &mut E

where E: Extend<Self::Item>, Self: Sized,

🔬This is a nightly-only experimental API. (iter_collect_into)

Collects all the items from an iterator into a collection.

fn partition<B, F>(self, f: F) -> (B, B)

where Self: Sized, B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it.

fn is_partitioned<P>(self, predicate: P) -> bool

where Self: Sized, P: FnMut(Self::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_is_partitioned)

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false.

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R

where Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

An iterator method that applies a function as long as it returns successfully, producing a single, final value.

fn try_for_each<F, R>(&mut self, f: F) -> R

where Self: Sized, F: FnMut(Self::Item) -> R, R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error.

fn fold<B, F>(self, init: B, f: F) -> B

where Self: Sized, F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, returning the final result.

fn reduce<F>(self, f: F) -> Option<Self::Item>

where Self: Sized, F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing operation.

fn try_reduce<R>( &mut self, f: impl FnMut(Self::Item, Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryType

where Self: Sized, R: Try<Output = Self::Item>, <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (iterator_try_reduce)

Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately.

fn all<F>(&mut self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate.

fn any<F>(&mut self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate.

fn find<P>(&mut self, predicate: P) -> Option<Self::Item>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate.

fn find_map<B, F>(&mut self, f: F) -> Option<B>

where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Applies function to the elements of iterator and returns the first non-none result.

fn try_find<R>( &mut self, f: impl FnMut(&Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType

where Self: Sized, R: Try<Output = bool>, <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (try_find)

Applies function to the elements of iterator and returns the first true result or the first error.

fn position<P>(&mut self, predicate: P) -> Option<usize>

where Self: Sized, P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index.

fn max(self) -> Option<Self::Item>

where Self: Sized, Self::Item: Ord,

Returns the maximum element of an iterator.

fn min(self) -> Option<Self::Item>

where Self: Sized, Self::Item: Ord,

Returns the minimum element of an iterator.

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>

where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the specified function.

fn max_by<F>(self, compare: F) -> Option<Self::Item>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the specified comparison function.

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>

where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the specified function.

fn min_by<F>(self, compare: F) -> Option<Self::Item>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the specified comparison function.

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)

where FromA: Default + Extend<A>, FromB: Default + Extend<B>, Self: Sized + Iterator<Item = (A, B)>,

Converts an iterator of pairs into a pair of containers.

fn copied<'a, T>(self) -> Copied<Self>

where T: Copy + 'a, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which copies all of its elements.

fn cloned<'a, T>(self) -> Cloned<Self>

where T: Clone + 'a, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which clones all of its elements.

fn cycle(self) -> Cycle<Self>

where Self: Sized + Clone,

Repeats an iterator endlessly.

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>

where Self: Sized,

🔬This is a nightly-only experimental API. (iter_array_chunks)

Returns an iterator over N elements of the iterator at a time.

fn sum<S>(self) -> S

where Self: Sized, S: Sum<Self::Item>,

Sums the elements of an iterator.

fn product<P>(self) -> P

where Self: Sized, P: Product<Self::Item>,

Iterates over the entire iterator, multiplying all the elements

fn cmp<I>(self, other: I) -> Ordering

where I: IntoIterator<Item = Self::Item>, Self::Item: Ord, Self: Sized,

Lexicographically compares the elements of this Iterator with those of another.

fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

fn partial_cmp<I>(self, other: I) -> Option<Ordering>

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Lexicographically compares the PartialOrd elements of this Iterator with those of another. The comparison works like short-circuit evaluation, returning a result without comparing the remaining elements. As soon as an order can be determined, the evaluation stops and a result is returned.

fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

fn eq<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are equal to those of another.

fn eq_by<I, F>(self, other: I, eq: F) -> bool

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_order_by)

Determines if the elements of this Iterator are equal to those of another with respect to the specified equality function.

fn ne<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are not equal to those of another.

fn lt<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less than those of another.

fn le<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less or equal to those of another.

fn gt<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than those of another.

fn ge<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than or equal to those of another.

fn is_sorted(self) -> bool

where Self: Sized, Self::Item: PartialOrd,

Checks if the elements of this iterator are sorted.

fn is_sorted_by<F>(self, compare: F) -> bool

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> bool,

Checks if the elements of this iterator are sorted using the given comparator function.

fn is_sorted_by_key<F, K>(self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> K, K: PartialOrd,

Checks if the elements of this iterator are sorted using the given key extraction function.