Struct Span

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

Represents a span in the SourceMap, bounded by an offset and a len

About offset

The offset of this Span is an absolute offset inside the SourceMap It doesn’t represent the offset relative to the file it was created from. This is done to avoid havind an additional field to identify the source file.

To get the base offset of a Span you can use the SourceMap::get_base_offset_of_span function

Fields

offset: usize

Offset of the span

len: usize

Length of the span

Implementations

impl Span

pub const fn dummy() -> Span

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

Joins two spans together. Returns the smallest Span that covers both.

pub fn slice<'a>(&self, base_offset: usize, src: &'a str) -> &'a str

Slices the given string with this span

base_offset is the base offset of the corresponding SourceFile for this Span

You can also use the SourceMap::slice function

See: about offset

Examples

Simple example with a single source file

use span::Span;

let src = "abcdefg";
let span = Span {
    offset: 1,
    len: 5,
};
let slice = span.slice(0, src);
assert_eq!("bcdef", slice);

Example with multiple source files

use span::{Span, source::SourceMap};

let src1 = "abcdefghi";
let src2 = "abcdefhij";

let mut source = SourceMap::default();
let offset1 = source.add_file_annon(src1.into()).offset();
let offset2 = source.add_file_annon(src2.into()).offset();

let span1 = Span {
    offset: offset1 + 3,
    len: 4,
};

let span2 = Span {
    offset: offset2 + 4,
    len: 2,
};

let slice1 = span1.slice(offset1, src1);
let slice2 = span2.slice(offset2, src1);

assert_eq!(slice1, "defg");
assert_eq!(slice2, "ef");

pub fn file_position(&self, base_offset: usize, src: &str) -> FilePosition

Gets the file position of this span in the given string slice

base_offset is the base offset of the corresponding SourceFile for this Span

You can also use the SourceMap::file_position function

See: about offset

pub const fn end_offset(&self) -> usize

Returns the end offset of the span. This is, the offset of the span plus it’s length

Trait Implementations

impl Clone for Span

fn clone(&self) -> Span

Returns a copy 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 Default for Span

fn default() -> Span

Returns the “default value” for a type.

impl Display for Span

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

Formats the value using the given formatter.

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 StructuralPartialEq for Span