Struct Sel 

pub struct Sel {
    pub anchor: Position,
    pub head: Position,
}

One selection: an anchor (the fixed end) and a head (the end a motion moves). Both are inclusive char positions — anchor == head is a bare caret, and a selection with extent covers [start, end] inclusive of both.

Units

Char columns, like hjkl_buffer::Edit and View::cursor — NOT the grapheme columns of crate::types::Pos. Mixing the two is silently wrong on multi-byte text.

Why the engine owns the anchor

A discipline could keep its own Vec of anchors beside Editor’s secondary carets, but shift_position may DROP a caret it cannot track, and a parallel Vec would then desync: anchors and heads would pair up wrong and the next edit would land on text the user never selected. Keeping both ends in one struct, shifted together by shift_sel, makes that class of bug unrepresentable — either the whole selection survives the edit or the whole selection is dropped.

The primary selection is deliberately asymmetric: its head is View::cursor and its anchor lives in the discipline’s own state (vim’s visual_anchor in VimState, helix’s anchor in HelixState). That split predates multi-cursor and unifying it would rewrite vim’s visual mode, so it stays. Only the secondary selections live here.

Fields

anchor: Position

The end that stays put while a motion runs.

head: Position

The end a motion moves; where an edit is applied.

Implementations

impl Sel

pub fn new(anchor: Position, head: Position) -> Self

A selection from anchor to head.

pub fn caret(p: Position) -> Self

A zero-width selection: anchor and head on the same position.

pub fn is_caret(&self) -> bool

True when the selection has no extent.

pub fn start(&self) -> Position

The earlier of the two ends, in document order.

pub fn end(&self) -> Position

The later of the two ends, in document order.

Trait Implementations

impl Clone for Sel

fn clone(&self) -> Sel

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Sel

impl Debug for Sel

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

Formats the value using the given formatter.

impl Eq for Sel

impl PartialEq for Sel

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Sel