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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
use std::ops::Add;
use unicode_segmentation::UnicodeSegmentation;
#[derive(Clone, Debug, Default, PartialEq)]
pub struct CursorPosition {
pub line: u32,
pub col: u32,
}
#[allow(dead_code)]
impl CursorPosition {
pub(crate) fn new(line: usize, col: usize) -> Self {
Self {
line: line as u32,
col: col as u32,
}
}
}
impl From<(usize, usize)> for CursorPosition {
fn from((line, col): (usize, usize)) -> Self {
Self::new(line, col)
}
}
/// CursorSpan is used to for reporting errors and defining corrections.
/// This is passed across the FFI and used by the editor.
#[derive(Clone, Debug, Default, PartialEq)]
pub struct CursorSpan {
pub from: CursorPosition,
pub to: CursorPosition,
}
/// CursorPosition + &str -> CursorSpan.
/// This is a convenient way of making CursorSpans.
impl Add<&str> for CursorPosition {
type Output = CursorSpan;
fn add(self, rhs: &str) -> Self::Output {
let mut line_count = 0;
let mut last_line = None;
for line in rhs.lines() {
line_count += 1;
last_line = Some(line);
}
if rhs.ends_with('\n') {
line_count += 1;
last_line = None;
}
let last_line_length = match last_line {
Some(line) => UnicodeSegmentation::graphemes(line, true).count(),
None => 0,
} as u32;
let to = match line_count {
0 => self.clone(),
1 => CursorPosition {
line: self.line,
col: self.col + last_line_length,
},
_ => CursorPosition {
line: self.line + line_count - 1,
col: last_line_length,
},
};
Self::Output { from: self, to }
}
}
impl Add<CursorSpan> for CursorPosition {
type Output = CursorSpan;
fn add(self, rhs: CursorSpan) -> Self::Output {
Self::Output {
from: self,
to: rhs.to,
}
}
}
#[cfg(test)]
mod unit_tests {
use super::*;
#[test]
fn test_add_str() {
// start at (10, 10) so we can check that things are zeroing properly.
let from = CursorPosition::new(10, 10);
assert_eq!(CursorPosition::new(10, 10), (from.clone() + "").to);
assert_eq!(CursorPosition::new(10, 11), (from.clone() + "0").to);
assert_eq!(CursorPosition::new(10, 12), (from.clone() + "01").to);
assert_eq!(CursorPosition::new(11, 1), (from.clone() + "\n0").to);
assert_eq!(CursorPosition::new(12, 1), (from.clone() + "\n\n0").to);
assert_eq!(CursorPosition::new(11, 0), (from.clone() + "\n").to);
assert_eq!(CursorPosition::new(12, 0), (from.clone() + "\n\n").to);
}
}