Struct Span 

pub struct Span {
    pub offset: u32,
    pub len: u32,
}

Source span with offset and length.

This type tracks a byte offset and length within a source document, useful for error reporting that can point back to the original source.

To use span tracking in your own types, define a wrapper struct with #[facet(metadata_container)] and a span field marked with #[facet(metadata = "span")]:

use facet::Facet;
use facet_reflect::Span;

#[derive(Debug, Clone, Facet)]
#[facet(metadata_container)]
pub struct Spanned<T> {
    pub value: T,
    #[facet(metadata = "span")]
    pub span: Option<Span>,
}

Fields

offset: u32

Byte offset from start of source (max 4GB).

len: u32

Length in bytes (max 4GB).

Implementations

impl Span

pub const fn new(offset: usize, len: usize) -> Span

Create a new span with the given offset and length.

Values larger than u32::MAX are saturated.

pub const fn is_unknown(&self) -> bool

Check if this span is unknown (zero offset and length).

pub const fn end(&self) -> usize

Get the end offset (offset + len).

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<(), Error>

Formats the value using the given formatter.

impl Default for Span

fn default() -> Span

Returns the “default value” for a type.

impl Display for Span

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

Formats the value using the given formatter.

impl Eq for Span

impl Facet<'_> for Span

const SHAPE: &'static Shape

The shape of this type, including: whether it’s a Struct, an Enum, something else?

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