Trait chumsky::span::Span

pub trait Span: Clone {
    type Context: Clone;
    type Offset: Clone;

    // Required methods
    fn new(context: Self::Context, range: Range<Self::Offset>) -> Self;
    fn context(&self) -> Self::Context;
    fn start(&self) -> Self::Offset;
    fn end(&self) -> Self::Offset;
}

A trait that describes a span over a particular range of inputs.

Spans typically consist of some context, such as the file they originated from, and a start/end offset. Spans are permitted to overlap one-another. The end offset must always be greater than or equal to the start offset.

Span is automatically implemented for Range<T> and [(C, Range<T>)].

Required Associated Types

type Context: Clone

Extra context used in a span.

This is usually some way to uniquely identity the source file that a span originated in such as the file’s path, URL, etc.

NOTE: Span contexts have no inherent meaning to Chumsky and can be anything. For example, Range<usize>’s implementation of Span simply uses [()] as its context.

type Offset: Clone

A type representing a span’s start or end offset from the start of the input.

Typically, usize is used.

NOTE: Offsets have no inherently meaning to Chumsky and are not used to decide how to prioritise errors. This means that it’s perfectly fine for tokens to have non-continuous spans that bear no relation to their actual location in the input stream. This is useful for languages with an AST-level macro system that need to correctly point to symbols in the macro input when producing errors.

Required Methods

fn new(context: Self::Context, range: Range<Self::Offset>) -> Self

Create a new span given a context and an offset range.

fn context(&self) -> Self::Context

Return the span’s context.

fn start(&self) -> Self::Offset

Return the start offset of the span.

fn end(&self) -> Self::Offset

Return the end offset of the span.

Object Safety

This trait is not object safe.

Implementations on Foreign Types

impl<C: Clone, T: Clone> Span for (C, Range<T>)

type Context = C

type Offset = T

fn new(context: Self::Context, range: Range<T>) -> Self

fn context(&self) -> Self::Context

fn start(&self) -> Self::Offset

fn end(&self) -> Self::Offset

impl<T: Clone + Ord> Span for Range<T>

type Context = ()

type Offset = T

fn new((): Self::Context, range: Self) -> Self

fn context(&self) -> Self::Context

fn start(&self) -> Self::Offset

fn end(&self) -> Self::Offset

Implementors