Struct source_span::Position

pub struct Position {
    pub line: usize,
    pub column: usize,
}

Position in a source file (line and column).

This holds the line and column position of a character in a source file. Some operations are available to move position in a file. In partular, the next method computes the next cursor position after reading a given char.

Display

The struct implements two different format traits:

• fmt::Display will format the position as line {line} column {column}
• fmt::Debug will format the position as {line}:{column}.

Both of them will display lines and columns starting at 1 even though the internal representation starts at 0.

Fields

line: usize

Line number, starting at 0.

column: usize

Column number, starting at 0.

Implementations

impl Position

pub const fn new(line: usize, column: usize) -> Self

Create a new position given a line and column.

Indexes starts at 0.

pub const fn end() -> Self

Return the maximum position.

Example

use source_span::Position;

assert_eq!(
	Position::end(),
	Position::new(usize::max_value(), usize::max_value())
	);

pub const fn next_column(&self) -> Self

Move to the next column.

pub const fn reset_column(&self) -> Self

Move to the begining of the line.

pub const fn next_line(&self) -> Self

Move to the next line, and reset the column position.

pub fn next<M: Metrics>(&self, c: char, metrics: &M) -> Self

Move to the position following the given char using the given Metrics.

Control characters

This crate is intended to help with incremental lexing/parsing. Therefore, any control character moving the cursor backward will be ignored: it will be treated as a 0-width character with no semantics.

New lines

The \n character is interpreted with the Unix semantics, as the new line (NL) character. It will reset the column position to 0 and move to the next line.

Tabulations

The \t will move the cursor to the next horizontal tab-top. The length of a tab-stop (in columns) is given by the metrics parameter.

Full-width characters

Note that, as for now, double-width characters of full-width characters are not supported by the DefaultMetrics. They will move the cursor by only one column as any other regular-width character. You are welcome to contribute to handle them.

pub fn shift<M: Metrics>(&mut self, c: char, metrics: &M)

pub fn from(&self, first: Self, last: Self) -> Span

Creates the span ending at this position (excluded) from first included to last included.

It is assumed that this position follows last. This is equivalent to Span::new(first, last, *self).

pub fn from_included(&self, first: Self, end: Self) -> Span

Creates the span ending at this position (included) from first included to end excluded.

It is assumed that end follows this position. This is equivalent to Span::new(first, *self, end).

pub fn to(&self, last: Self, end: Self) -> Span

Creates the span starting from this position to last included and end excluded.

It is assumed that end follows last. This is equivalent to Span::new(*self, last, end).

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 Default for Position

fn default() -> Position

Returns the “default value” for a type.

impl Display for Position

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

Formats the value using the given formatter.

impl From<Position> for Span

fn from(pos: Position) -> Self

Performs the conversion.

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, 

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

Compares and returns the maximum of two values.

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

Compares and returns the minimum of two values.

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

Restrict a value to a certain interval.

impl PartialEq<Position> for Position

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

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Position) -> bool

This method tests for !=.

impl PartialOrd<Position> 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

This method tests less than (for self and other) and is used by the < operator.

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

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

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

This method tests greater than (for self and other) and is used by the > operator.

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

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

impl Copy for Position

impl Eq for Position

impl StructuralEq for Position

impl StructuralPartialEq for Position