Struct Span 

pub struct Span { /* private fields */ }

Range of Input.

Spans are specific to the input chain they were created in as the range is stored as raw start and end pointers.

You can create a span from either Input::span() or from a raw slice via Span::from().

Implementations

impl Span

pub fn len(self) -> usize

Returns the number of bytes spanned.

pub fn is_empty(self) -> bool

Returns true if no bytes are spanned.

pub fn is_within(self, other: Span) -> bool

Returns true if the span is completely within the bounds of the specified parent.

Examples

use dangerous::Span;

let bytes = [0_u8; 64];

// Within
let parent = Span::from(&bytes[16..32]);
let child = Span::from(&bytes[20..24]);
assert!(child.is_within(parent));
assert!(parent.is_within(parent));

// Left out of bound
let parent = Span::from(&bytes[16..32]);
let child = Span::from(&bytes[15..24]);
assert!(!child.is_within(parent));

// Right out of bound
let parent = Span::from(&bytes[16..32]);
let child = Span::from(&bytes[20..33]);
assert!(!child.is_within(parent));

// Both out of bound
let parent = Span::from(&bytes[16..32]);
let child = Span::from(&bytes[15..33]);
assert!(!child.is_within(parent));

pub fn is_start_of(self, other: Span) -> bool

Returns true if self points to the start of other, spanning no bytes.

Example

use dangerous::Span;

let bytes = &[1, 2, 3, 4][..];
let span = Span::from(bytes);

assert!(span.start().is_start_of(span));
assert!(!span.is_start_of(span));

pub fn is_end_of(self, other: Span) -> bool

Returns true if self points to the end of other, spanning no bytes.

Example

use dangerous::Span;

let bytes = &[1, 2, 3, 4][..];
let span = Span::from(bytes);

assert!(span.end().is_end_of(span));
assert!(!span.is_end_of(span));

pub fn is_overlapping_start_of(self, other: Span) -> bool

Returns true if self overlaps the start of other.

Example

use dangerous::Span;

let all = b"0123456789";
let a = Span::from(&all[0..9]);
let b = Span::from(&all[6..9]);

assert!(a.is_overlapping_start_of(b));

pub fn is_overlapping_end_of(self, other: Span) -> bool

Returns true if self overlaps the end of other.

pub fn is_start_within(self, other: Span) -> bool

Returns true if self’s start is within other.

pub fn is_end_within(self, other: Span) -> bool

Returns true if self’s end is within other.

pub fn start(self) -> Self

Returns a span pointing to the start of self, spanning no bytes.

pub fn end(self) -> Self

Returns a span pointing to the end of self, spanning no bytes.

pub fn of<P>(self, parent: P) -> Option<P>

where P: Parent,

Returns the sub slice of the provided parent self refers to or None if self is not within the parent or does not align with start and end token boundaries.

You can get a span of Input, &str or &[u8].

Example

use dangerous::Span;

let parent = &[1, 2, 3, 4][..];
let sub = &parent[1..2];
assert_eq!(Span::from(sub).of(parent), Some(sub));

let non_span = Span::from(&[1, 2, 2, 4][..]);
assert_eq!(non_span.of(parent), None);

pub fn range_of(self, parent: Span) -> Option<Range<usize>>

Returns Some(Range) with the start and end offsets of self within the parent. None is returned if self is not within in the parent.

Example

use dangerous::Span;

let parent = &[1, 2, 3, 4][..];
let sub_range = 1..2;
let sub = &parent[sub_range.clone()];

assert_eq!(Span::from(sub).range_of(parent.into()), Some(sub_range))

pub fn non_empty(self) -> Option<Self>

Returns None if the span is empty, Some(Self) if not.

Example

use dangerous::Span;

let bytes = &[0][..];
assert!(Span::from(bytes).non_empty().is_some());

let bytes = &[][..];
assert!(Span::from(bytes).non_empty().is_none());

pub fn debug_for(self, input: MaybeString<'_>) -> DebugFor<'_>

Wraps the span with improved debugging support given the containing input.

Trait Implementations

impl Clone for Span

fn clone(&self) -> Span

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Span

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

Formats the value using the given formatter.

impl<'o> Dependant<'o> for Span

Available on crate feature zc only.

type Static = Span

Always the exact same structure as Self but instead with a 'static lifetime.

impl DisplayBase for Span

fn fmt(&self, w: &mut dyn Write) -> Result

Formats self given the provided Write.

impl From<&[u8]> for Span

fn from(value: &[u8]) -> Self

Converts to this type from the input type.

impl From<&str> for Span

fn from(value: &str) -> Self

Converts to this type from the input type.

impl Hash for Span

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Span

fn eq(&self, other: &Span) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Span

impl Eq for Span

impl Send for Span

impl StructuralPartialEq for Span

impl Sync for Span