Struct Position

pub struct Position { /* private fields */ }

A cursor position in a &str which provides useful methods to manually parse that string.

Implementations

impl Position

pub fn new(input: Arc<str>, pos: usize) -> Option<Position>

Attempts to create a new Position at the given position. If the specified position is an invalid index, or the specified position is not a valid UTF8 boundary, then None is returned.

Examples

let cheart = '💖';
let heart: Arc<str> = Arc::from("💖");
assert_eq!(Position::new(heart.clone(), 1), None);
assert_ne!(Position::new(heart, cheart.len_utf8()), None);

pub fn from_start(input: Arc<str>) -> Position

Creates a Position at the start of a &str.

Examples

let start = Position::from_start(Arc::from(""));
assert_eq!(start.pos(), 0);

pub fn pos(&self) -> usize

Returns the byte position of this Position as a usize.

Examples

let input: Arc<str> = Arc::from("ab");
let mut start = Position::from_start(input);

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

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

Creates a Span from two Positions.

Panics

Panics if the positions come from different inputs.

Examples

let input: Arc<str> = Arc::from("ab");
let start = Position::from_start(input);
let span = start.span(&start.clone());

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

pub fn line_col(&self) -> (usize, usize)

Returns the line and column number of this Position.

Examples

enum Rule {}

let input: Arc<str> = Arc::from("\na");
let mut state: Box<pest::ParserState<Rule>> = pest::ParserState::new(input);
let mut result = state.match_string("\na");
assert!(result.is_ok());
assert_eq!(result.unwrap().position().line_col(), (2, 2));

pub fn line_of(&self) -> &str

Returns the entire line of the input that contains this Position.

Examples

enum Rule {}

let input: Arc<str> = Arc::from("\na");
let mut state: Box<pest::ParserState<Rule>> = pest::ParserState::new(input);
let mut result = state.match_string("\na");
assert!(result.is_ok());
assert_eq!(result.unwrap().position().line_of(), "a");

Trait Implementations

impl Clone for Position

fn clone(&self) -> Position

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Position

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

Formats the value using the given formatter.

impl Hash for Position

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 Ord for Position

fn cmp(&self, other: &Position) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Position

fn eq(&self, other: &Position) -> 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 PartialOrd for Position

fn partial_cmp(&self, other: &Position) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Eq for Position