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|
use crate::{
graphemes::{nth_next_grapheme_boundary, RopeGraphemes},
Rope, RopeSlice,
};
/// Represents a single point in a text buffer. Zero indexed.
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
pub struct Position {
pub row: usize,
pub col: usize,
}
impl Position {
pub const fn new(row: usize, col: usize) -> Self {
Self { row, col }
}
pub const fn is_zero(self) -> bool {
self.row == 0 && self.col == 0
}
// TODO: generalize
pub fn traverse(self, text: &crate::Tendril) -> Self {
let Self { mut row, mut col } = self;
// TODO: there should be a better way here
for ch in text.chars() {
if ch == '\n' {
row += 1;
col = 0;
} else {
col += 1;
}
}
Self { row, col }
}
}
impl From<(usize, usize)> for Position {
fn from(tuple: (usize, usize)) -> Self {
Self {
row: tuple.0,
col: tuple.1,
}
}
}
impl From<Position> for tree_sitter::Point {
fn from(pos: Position) -> Self {
Self::new(pos.row, pos.col)
}
}
/// 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 = RopeGraphemes::new(text.slice(line_start..pos)).count();
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);
// line_start + col
nth_next_grapheme_boundary(text, line_start, col)
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_ordering() {
// (0, 5) is less than (1, 0)
assert!(Position::new(0, 5) < Position::new(1, 0));
}
#[test]
fn test_coords_at_pos() {
let text = Rope::from("ḧëḷḷö\nẅöṛḷḋ");
let slice = text.slice(..);
// assert_eq!(coords_at_pos(slice, 0), (0, 0).into());
// assert_eq!(coords_at_pos(slice, 5), (0, 5).into()); // position on \n
// assert_eq!(coords_at_pos(slice, 6), (1, 0).into()); // position on w
// assert_eq!(coords_at_pos(slice, 7), (1, 1).into()); // position on o
// assert_eq!(coords_at_pos(slice, 10), (1, 4).into()); // position on d
// test with grapheme clusters
let text = Rope::from("a̐éö̲\r\n");
let slice = text.slice(..);
assert_eq!(coords_at_pos(slice, 0), (0, 0).into());
assert_eq!(coords_at_pos(slice, 2), (0, 1).into());
assert_eq!(coords_at_pos(slice, 4), (0, 2).into());
assert_eq!(coords_at_pos(slice, 7), (0, 3).into());
let text = Rope::from("किमपि");
let slice = text.slice(..);
assert_eq!(coords_at_pos(slice, 0), (0, 0).into());
assert_eq!(coords_at_pos(slice, 2), (0, 1).into());
assert_eq!(coords_at_pos(slice, 3), (0, 2).into());
assert_eq!(coords_at_pos(slice, 5), (0, 3).into());
}
#[test]
fn test_pos_at_coords() {
let text = Rope::from("ḧëḷḷö\nẅöṛḷḋ");
let slice = text.slice(..);
assert_eq!(pos_at_coords(slice, (0, 0).into()), 0);
assert_eq!(pos_at_coords(slice, (0, 5).into()), 5); // position on \n
assert_eq!(pos_at_coords(slice, (1, 0).into()), 6); // position on w
assert_eq!(pos_at_coords(slice, (1, 1).into()), 7); // position on o
assert_eq!(pos_at_coords(slice, (1, 4).into()), 10); // position on d
// test with grapheme clusters
let text = Rope::from("a̐éö̲\r\n");
let slice = text.slice(..);
assert_eq!(pos_at_coords(slice, (0, 0).into()), 0);
assert_eq!(pos_at_coords(slice, (0, 1).into()), 2);
assert_eq!(pos_at_coords(slice, (0, 2).into()), 4);
assert_eq!(pos_at_coords(slice, (0, 3).into()), 7); // \r\n is one char here
assert_eq!(pos_at_coords(slice, (0, 4).into()), 9);
let text = Rope::from("किमपि");
// 2 - 1 - 2 codepoints
// TODO: delete handling as per https://news.ycombinator.com/item?id=20058454
let slice = text.slice(..);
assert_eq!(pos_at_coords(slice, (0, 0).into()), 0);
assert_eq!(pos_at_coords(slice, (0, 1).into()), 2);
assert_eq!(pos_at_coords(slice, (0, 2).into()), 3);
assert_eq!(pos_at_coords(slice, (0, 3).into()), 5); // eol
}
}
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