Struct Span

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pub struct Span<'i> { /* private fields */ }

Expand description

A span over a &str. It is created from either two Positions or from a Pair.

Implementations§

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impl<'i> Span<'i>

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pub fn new(input: &str, start: usize, end: usize) -> Option<Span<'_>>

Attempts to create a new span. Will return None if input[start..end] is an invalid index into input.

§Examples

let input = "Hello!";
assert_eq!(None, Span::new(input, 100, 0));
assert!(Span::new(input, 0, input.len()).is_some());

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pub fn get(&self, range: impl RangeBounds<usize>) -> Option<Span<'i>>

Attempts to create a new span based on a sub-range.

use pest::Span;
let input = "Hello World!";
let world = Span::new(input, 6, input.len()).unwrap();
let orl = world.get(1..=3);
assert!(orl.is_some());
assert_eq!(orl.unwrap().as_str(), "orl");

§Examples

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pub fn start(&self) -> usize

Returns the Span’s start byte position as a usize.

§Examples

let input = "ab";
let start = Position::from_start(input);
let end = start.clone();
let span = start.span(&end);

assert_eq!(span.start(), 0);

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pub fn end(&self) -> usize

Returns the Span’s end byte position as a usize.

§Examples

let input = "ab";
let start = Position::from_start(input);
let end = start.clone();
let span = start.span(&end);

assert_eq!(span.end(), 0);

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pub fn start_pos(&self) -> Position<'i>

Returns the Span’s start Position.

§Examples

let input = "ab";
let start = Position::from_start(input);
let end = start.clone();
let span = start.clone().span(&end);

assert_eq!(span.start_pos(), start);

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pub fn end_pos(&self) -> Position<'i>

Returns the Span’s end Position.

§Examples

let input = "ab";
let start = Position::from_start(input);
let end = start.clone();
let span = start.span(&end);

assert_eq!(span.end_pos(), end);

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pub fn split(self) -> (Position<'i>, Position<'i>)

Splits the Span into a pair of Positions.

§Examples

let input = "ab";
let start = Position::from_start(input);
let end = start.clone();
let span = start.clone().span(&end);

assert_eq!(span.split(), (start, end));

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pub fn as_str(&self) -> &'i str

Captures a slice from the &str defined by the Span.

§Examples

enum Rule {}

let input = "abc";
let mut state: Box<pest::ParserState<'_, Rule>> = pest::ParserState::new(input).skip(1).unwrap();
let start_pos = state.position().clone();
state = state.match_string("b").unwrap();
let span = start_pos.span(&state.position().clone());
assert_eq!(span.as_str(), "b");

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pub fn get_input(&self) -> &'i str

Returns the input string of the Span.

This function returns the input string of the Span as a &str. This is the source string from which the Span was created. The returned &str can be used to examine the contents of the Span or to perform further processing on the string.

§Examples


// Example: Get input string from a span
let input = "abc\ndef\nghi";
let span = Span::new(input, 1, 7).unwrap();
assert_eq!(span.get_input(), input);

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pub fn lines(&self) -> Lines<'_> ⓘ

Iterates over all lines (partially) covered by this span. Yielding a &str for each line.

§Examples

enum Rule {}

let input = "a\nb\nc";
let mut state: Box<pest::ParserState<'_, Rule>> = pest::ParserState::new(input).skip(2).unwrap();
let start_pos = state.position().clone();
state = state.match_string("b\nc").unwrap();
let span = start_pos.span(&state.position().clone());
assert_eq!(span.lines().collect::<Vec<_>>(), vec!["b\n", "c"]);

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pub fn lines_span(&self) -> LinesSpan<'_> ⓘ

Iterates over all lines (partially) covered by this span. Yielding a Span for each line.

§Examples

enum Rule {}

let input = "a\nb\nc";
let mut state: Box<pest::ParserState<'_, Rule>> = pest::ParserState::new(input).skip(2).unwrap();
let start_pos = state.position().clone();
state = state.match_string("b\nc").unwrap();
let span = start_pos.span(&state.position().clone());
assert_eq!(span.lines_span().collect::<Vec<_>>(), vec![Span::new(input, 2, 4).unwrap(), Span::new(input, 4, 5).unwrap()]);