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use buffer::Position;
/// A two-position type, representing a span of characters.
#[derive(Clone, Debug, PartialEq)]
pub struct Range {
start: Position,
end: Position,
}
impl Range {
/// Creates a new buffer range. Checks and swaps arguments
/// in the event that the end precedes the start.
pub fn new(start: Position, end: Position) -> Range {
// Ensure that the end does not precede the start.
if start > end {
Range{ start: end, end: start }
} else {
Range{ start: start, end: end }
}
}
pub fn start(&self) -> Position {
self.start
}
pub fn end(&self) -> Position {
self.end
}
/// Whether or not the range includes the specified position.
/// The range is exclusive, such that its ending position is not included.
///
/// # Examples
///
/// ```
/// use scribe::buffer::{Position, Range};
///
/// // Builder a range.
/// let range = Range::new(
/// Position{ line: 0, offset: 0 },
/// Position{ line: 1, offset: 5 }
/// );
///
/// assert!(range.includes(
/// &Position{ line: 1, offset: 0 }
/// ));
///
/// assert!(range.includes(
/// &Position{ line: 1, offset: 4 }
/// ));
///
/// assert!(!range.includes(
/// &Position{ line: 1, offset: 5 }
/// ));
/// ```
pub fn includes(&self, position: &Position) -> bool {
position >= &self.start() && position < &self.end()
}
}
#[cfg(test)]
mod tests {
use buffer::Position;
use super::Range;
#[test]
fn new_does_not_swap_values_if_end_does_not_precede_start() {
let mut start = Position { line: 0, offset: 4 };
let mut end = Position { line: 1, offset: 1 };
let mut range = Range::new(start, end);
assert_eq!(range.start(), start);
assert_eq!(range.end(), end);
start = Position { line: 0, offset: 4 };
end = Position { line: 0, offset: 4 };
range = Range::new(start, end);
assert_eq!(range.start(), start);
assert_eq!(range.end(), end);
}
#[test]
fn new_swaps_start_and_end_when_end_precedes_start() {
let start = Position { line: 1, offset: 4 };
let end = Position { line: 1, offset: 1 };
let range = Range::new(start, end);
assert_eq!(range.start(), end);
assert_eq!(range.end(), start);
}
}