Struct Span 

pub struct Span { /* private fields */ }

A byte range representing a location in source text.

Spans track the start and end byte offsets of syntax elements, enabling precise source mapping for diagnostics, suggestions, and tooling.

Examples

// Create a span covering bytes 10-25
let span = Span::new(10..25);
assert_eq!(span.start(), 10);
assert_eq!(span.end(), 25);
assert_eq!(span.len(), 15);

// Combine two spans into one that covers both
let other = Span::new(30..40);
let combined = span.union(other);
assert_eq!(combined.start(), 10);
assert_eq!(combined.end(), 40);

Implementations

impl Span

pub fn new(range: Range<usize>) -> Self

Creates a new Span from a byte range.

Arguments

• range - The start..end byte offset range.

pub fn empty() -> Self

Creates a zero-length, empty span.

pub fn start(&self) -> usize

Returns the start byte offset.

pub fn end(&self) -> usize

Returns the end byte offset.

pub fn len(&self) -> usize

Returns the length of the span in bytes.

Panics

Panics if end is less than start.

pub fn is_empty(&self) -> bool

Returns true if the span has zero length.

pub fn union(&self, other: Span) -> Span

Creates the smallest span encompassing both self and other.

If either span is empty, the other is returned unchanged.

Arguments

• other - The span to merge with.

pub fn shift(self, base: usize) -> Span

Returns a new span with both offsets translated by base bytes.

This shifts the span’s position in the virtual address space without changing its length.

Arguments

• base - Number of bytes to add to both start and end.

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 Copy for Span

impl Debug for Span

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

Formats the value using the given formatter.

impl Default for Span

fn default() -> Self

Returns the “default value” for a type.

impl Eq for Span

impl From<Range<usize>> for Span

fn from(range: Range<usize>) -> 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 StructuralPartialEq for Span