Struct Cursor 

pub struct Cursor {
    pub position: Position,
    pub anchor: Option<Position>,
    pub preferred_column: Option<usize>,
}

Cursor state within a buffer.

The cursor tracks the current position, an optional selection anchor, and a preferred column for vertical movement.

Selection

When anchor is Some, a selection extends from anchor to position. The selection can be in either direction (anchor before or after position).

Preferred Column

When moving vertically through lines of varying lengths, the cursor attempts to maintain its horizontal position. The preferred_column stores this target column.

Example

use reovim_kernel::api::v1::*;

let mut cursor = Cursor::new(Position::new(0, 5));

// Start a selection
cursor.start_selection();
cursor.position = Position::new(0, 10);

// Get normalized bounds (start before end)
let (start, end) = cursor.selection_bounds().unwrap();
assert_eq!(start, Position::new(0, 5));
assert_eq!(end, Position::new(0, 10));

Fields

position: Position

Current cursor position.

anchor: Option<Position>

Selection anchor (if selection is active).

When Some, a selection extends from anchor to position.

preferred_column: Option<usize>

Preferred column for vertical movement (j/k).

This preserves horizontal position when navigating through lines of varying lengths.

Implementations

impl Cursor

pub const fn new(position: Position) -> Self

Create a new cursor at the given position.

pub const fn origin() -> Self

Create a cursor at the origin (0, 0).

pub const fn start_selection(&mut self)

Start a selection at the current position.

pub const fn clear_selection(&mut self)

Clear the current selection.

pub const fn has_selection(&self) -> bool

Check if a selection is active.

pub fn selection_bounds(&self) -> Option<(Position, Position)>

Get the selection bounds (start, end) in document order.

Returns None if no selection is active. The returned positions are always ordered (start <= end).

pub const fn update_preferred_column(&mut self)

Set preferred column to current column.

Call this after horizontal movements to update the target column for subsequent vertical movements.

pub const fn clear_preferred_column(&mut self)

Clear preferred column.

Call this after horizontal movements that should reset the vertical movement target.

pub fn effective_column(&self) -> usize

Get the effective column for vertical movement.

Returns the preferred column if set, otherwise the current column.

Trait Implementations

impl Clone for Cursor

fn clone(&self) -> Cursor

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Cursor

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

Formats the value using the given formatter.

impl Default for Cursor

fn default() -> Cursor

Returns the “default value” for a type.

impl PartialEq for Cursor

fn eq(&self, other: &Cursor) -> 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 Cursor

impl Eq for Cursor

impl StructuralPartialEq for Cursor