use crate::graphemes::{nth_next_grapheme_boundary, nth_prev_grapheme_boundary}; use crate::{Buffer, Selection, SelectionRange}; /// A state represents the current editor state of a single buffer. pub struct State { doc: Buffer, selection: Selection, } #[derive(Copy, Clone, PartialEq, Eq)] pub enum Direction { Forward, Backward, } #[derive(Copy, Clone, PartialEq, Eq)] pub enum Granularity { Character, Word, Line, // LineBoundary } impl State { #[must_use] pub fn new(doc: Buffer) -> Self { Self { doc, selection: Selection::single(0, 0), } } // TODO: buf/selection accessors // update/transact: // update(desc) => transaction ? transaction.doc() for applied doc // transaction.apply(doc) // doc.transact(fn -> ... end) // replaceSelection (transaction that replaces selection) // changeByRange // changes // slice // // getters: // tabSize // indentUnit // languageDataAt() // // config: // indentation // tabSize // lineUnit // syntax // foldable // changeFilter/transactionFilter pub fn move_pos( &self, pos: usize, dir: Direction, granularity: Granularity, n: usize, ) -> usize { let text = &self.doc.contents; match (dir, granularity) { (Direction::Backward, Granularity::Character) => { nth_prev_grapheme_boundary(&text.slice(..), pos, n) } (Direction::Forward, Granularity::Character) => { nth_next_grapheme_boundary(&text.slice(..), pos, n) } _ => pos, } } pub fn move_selection( &self, sel: Selection, dir: Direction, granularity: Granularity, // TODO: n ) -> Selection { // TODO: move all selections according to normal cursor move semantics by collapsing it // into cursors and moving them vertically let ranges = sel.ranges.into_iter().map(|range| { // let pos = if !range.is_empty() { // // if selection already exists, bump it to the start or end of current select first // if dir == Direction::Backward { // range.from() // } else { // range.to() // } // } else { let pos = self.move_pos(range.head, dir, granularity, 1) // }; SelectionRange::new(pos, pos) }); Selection::new(ranges.collect(), sel.primary_index) // TODO: update selection in state via transaction } pub fn extend_selection( &self, sel: Selection, dir: Direction, granularity: Granularity, n: usize, ) -> Selection { let ranges = sel.ranges.into_iter().map(|range| { let pos = self.move_pos(range.head, dir, granularity, n); SelectionRange::new(range.anchor, pos) }); Selection::new(ranges.collect(), sel.primary_index) // TODO: update selection in state via transaction } }