Struct logos::SpannedIter

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

Iterator that pairs tokens with their position in the source.

Look at Lexer::spanned for documentation.

Methods from Deref<Target = Lexer<'source, Token>>

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

Source from which this Lexer is reading tokens.

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 99)

fn parse_value<'source>(lexer: &mut Lexer<'source, 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<'source>(lexer: &mut Lexer<'source, 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<'source>(lexer: &mut Lexer<'source, 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))
}

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

Get a string slice of the current token.

Examples found in repository

examples/extras.rs (line 70)

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() {
        match token {
            Ok(Token::Word((line, column))) => {
                println!("Word '{}' found at ({}, {})", lex.slice(), line, column);
            }
            _ => (),
        }
    }
}

examples/custom_error.rs (line 48)

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)));
    assert_eq!(lex.slice(), "é");

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

    assert_eq!(lex.next(), 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 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 SpannedIter<'source, Token>

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

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'source, Token> Deref for SpannedIter<'source, Token>

where Token: Logos<'source>,

type Target = Lexer<'source, Token>

The resulting type after dereferencing.

fn deref(&self) -> &Lexer<'source, Token>

Dereferences the value.

impl<'source, Token> DerefMut for SpannedIter<'source, Token>

where Token: Logos<'source>,

fn deref_mut(&mut self) -> &mut Lexer<'source, Token>

Mutably dereferences the value.

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

where Token: Logos<'source>,

type Item = (Result<Token, <Token as Logos<'source>>::Error>, Range<usize>)

The type of the elements being iterated over.

fn next(&mut self) -> Option<Self::Item>

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_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 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,

Borrows an iterator, rather than consuming it.

fn collect<B>(self) -> B

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

Transforms an iterator into a collection.

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<F, R>( &mut self, f: F ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryType

where Self: Sized, F: FnMut(Self::Item, Self::Item) -> R, 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<F, R>( &mut self, f: F ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType

where Self: Sized, F: FnMut(&Self::Item) -> R, 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_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: 'a + Copy, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which copies all of its elements.

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

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

Creates an iterator which clones all of its elements.

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_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_by<F>(self, compare: F) -> bool

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

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

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,

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

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