use crate::graphemes::{nth_next_grapheme_boundary, nth_prev_grapheme_boundary, RopeGraphemes}; use crate::syntax::LOADER; use crate::{ChangeSet, Diagnostic, Position, Range, Rope, RopeSlice, Selection, Syntax}; use anyhow::Error; /// A state represents the current editor state of a single buffer. #[derive(Clone)] pub struct State { // TODO: fields should be private but we need to refactor commands.rs first pub doc: Rope, pub 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: Rope) -> Self { Self { doc, selection: Selection::single(0, 0), } } // TODO: doc/selection accessors // TODO: be able to take either Rope or RopeSlice #[inline] pub fn doc(&self) -> &Rope { &self.doc } #[inline] pub fn selection(&self) -> &Selection { &self.selection } // pub fn doc(&self, range: R) -> RopeSlice // where // R: std::ops::RangeBounds, // { // self.doc.slice(range) // } // 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 // TODO: move that accepts a boundary matcher fn/list, we keep incrementing until we hit // a boundary // TODO: edits, does each keypress trigger a full command? I guess it's adding to the same // transaction // There should be three pieces of the state: current transaction, the original doc, "preview" // of the new state. // 1. apply the newly generated keypress as a transaction // 2. compose onto a ongoing transaction // 3. on insert mode leave, that transaction gets stored into undo history pub fn move_pos( &self, pos: usize, dir: Direction, granularity: Granularity, count: usize, ) -> usize { let text = &self.doc; match (dir, granularity) { (Direction::Backward, Granularity::Character) => { // Clamp to line let line = text.char_to_line(pos); let start = text.line_to_char(line); std::cmp::max( nth_prev_grapheme_boundary(&text.slice(..), pos, count), start, ) } (Direction::Forward, Granularity::Character) => { // Clamp to line let line = text.char_to_line(pos); // Line end is pos at the start of next line - 1 // subtract another 1 because the line ends with \n let end = text.line_to_char(line + 1).saturating_sub(2); std::cmp::min(nth_next_grapheme_boundary(&text.slice(..), pos, count), end) } (Direction::Forward, Granularity::Word) => { Self::move_next_word_start(&text.slice(..), pos) } (Direction::Backward, Granularity::Word) => { Self::move_prev_word_start(&text.slice(..), pos) } (_, Granularity::Line) => move_vertically(&text.slice(..), dir, pos, count), _ => pos, } } pub fn move_next_word_start(slice: &RopeSlice, mut pos: usize) -> usize { // TODO: confirm it's fine without using graphemes, I think it should be let ch = slice.char(pos); let next = slice.char(pos.saturating_add(1)); if categorize(ch) != categorize(next) { pos += 1; } // refetch let ch = slice.char(pos); if is_word(ch) { skip_over_next(slice, &mut pos, is_word); } else if ch.is_ascii_punctuation() { skip_over_next(slice, &mut pos, |ch| ch.is_ascii_punctuation()); } // TODO: don't include newline? skip_over_next(slice, &mut pos, |ch| ch.is_ascii_whitespace()); pos } pub fn move_prev_word_start(slice: &RopeSlice, mut pos: usize) -> usize { // TODO: confirm it's fine without using graphemes, I think it should be let ch = slice.char(pos); let prev = slice.char(pos.saturating_sub(1)); // TODO: just return original pos if at start if categorize(ch) != categorize(prev) { pos -= 1; } // TODO: skip while eol // TODO: don't include newline? skip_over_prev(slice, &mut pos, |ch| ch.is_ascii_whitespace()); // refetch let ch = slice.char(pos); if is_word(ch) { skip_over_prev(slice, &mut pos, is_word); } else if ch.is_ascii_punctuation() { skip_over_prev(slice, &mut pos, |ch| ch.is_ascii_punctuation()); } pos.saturating_add(1) } pub fn move_next_word_end(slice: &RopeSlice, mut pos: usize, _count: usize) -> usize { // TODO: confirm it's fine without using graphemes, I think it should be let ch = slice.char(pos); let next = slice.char(pos.saturating_add(1)); if categorize(ch) != categorize(next) { pos += 1; } // TODO: don't include newline? skip_over_next(slice, &mut pos, |ch| ch.is_ascii_whitespace()); // refetch let ch = slice.char(pos); if is_word(ch) { skip_over_next(slice, &mut pos, is_word); } else if ch.is_ascii_punctuation() { skip_over_next(slice, &mut pos, |ch| ch.is_ascii_punctuation()); } pos.saturating_sub(1) } pub fn move_selection( &self, dir: Direction, granularity: Granularity, count: usize, ) -> Selection { // move all selections according to normal cursor move semantics by collapsing it // into cursors and moving them vertically self.selection.transform(|range| { let pos = self.move_pos(range.head, dir, granularity, count); Range::new(pos, pos) }) } pub fn extend_selection( &self, dir: Direction, granularity: Granularity, count: usize, ) -> Selection { self.selection.transform(|range| { let pos = self.move_pos(range.head, dir, granularity, count); Range::new(range.anchor, pos) }) } } /// Convert a character index to (line, column) coordinates. pub fn coords_at_pos(text: &RopeSlice, pos: usize) -> Position { let line = text.char_to_line(pos); let line_start = text.line_to_char(line); let col = text.slice(line_start..pos).len_chars(); Position::new(line, col) } /// Convert (line, column) coordinates to a character index. pub fn pos_at_coords(text: &RopeSlice, coords: Position) -> usize { let Position { row, col } = coords; let line_start = text.line_to_char(row); nth_next_grapheme_boundary(text, line_start, col) } fn move_vertically(text: &RopeSlice, dir: Direction, pos: usize, count: usize) -> usize { let Position { row, col } = coords_at_pos(text, pos); let new_line = match dir { Direction::Backward => row.saturating_sub(count), Direction::Forward => std::cmp::min(row.saturating_add(count), text.len_lines() - 1), }; // convert to 0-indexed, subtract another 1 because len_chars() counts \n let new_line_len = text.line(new_line).len_chars().saturating_sub(2); let new_col = if new_line_len < col { // TODO: preserve horiz here new_line_len } else { col }; pos_at_coords(text, Position::new(new_line, new_col)) } // used for by-word movement fn is_word(ch: char) -> bool { ch.is_alphanumeric() || ch == '_' } #[derive(Debug, Eq, PartialEq)] enum Category { Whitespace, EOL, Word, Punctuation, } fn categorize(ch: char) -> Category { if ch == '\n' { Category::EOL } else if ch.is_ascii_whitespace() { Category::Whitespace } else if ch.is_ascii_punctuation() { Category::Punctuation } else if ch.is_ascii_alphanumeric() { Category::Word } else { unreachable!() } } fn skip_over_next(slice: &RopeSlice, pos: &mut usize, fun: F) where F: Fn(char) -> bool, { let mut chars = slice.chars_at(*pos); for ch in chars { if !fun(ch) { break; } *pos += 1; } } fn skip_over_prev(slice: &RopeSlice, pos: &mut usize, fun: F) where F: Fn(char) -> bool, { // need to +1 so that prev() includes current char let mut chars = slice.chars_at(*pos + 1); while let Some(ch) = chars.prev() { if !fun(ch) { break; } *pos -= 1; } } #[cfg(test)] mod test { use super::*; #[test] fn test_coords_at_pos() { let text = Rope::from("ḧëḷḷö\nẅöṛḷḋ"); assert_eq!(coords_at_pos(&text.slice(..), 0), (0, 0).into()); assert_eq!(coords_at_pos(&text.slice(..), 5), (0, 5).into()); // position on \n assert_eq!(coords_at_pos(&text.slice(..), 6), (1, 0).into()); // position on w assert_eq!(coords_at_pos(&text.slice(..), 7), (1, 1).into()); // position on o assert_eq!(coords_at_pos(&text.slice(..), 10), (1, 4).into()); // position on d } #[test] fn test_pos_at_coords() { let text = Rope::from("ḧëḷḷö\nẅöṛḷḋ"); assert_eq!(pos_at_coords(&text.slice(..), (0, 0).into()), 0); assert_eq!(pos_at_coords(&text.slice(..), (0, 5).into()), 5); // position on \n assert_eq!(pos_at_coords(&text.slice(..), (1, 0).into()), 6); // position on w assert_eq!(pos_at_coords(&text.slice(..), (1, 1).into()), 7); // position on o assert_eq!(pos_at_coords(&text.slice(..), (1, 4).into()), 10); // position on d } #[test] fn test_vertical_move() { let text = Rope::from("abcd\nefg\nwrs"); let pos = pos_at_coords(&text.slice(..), (0, 4).into()); let slice = text.slice(..); assert_eq!( coords_at_pos(&slice, move_vertically(&slice, Direction::Forward, pos, 1)), (1, 2).into() ); } }