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use std::cmp::Ordering;
use std::fmt::{self, Debug, Formatter};
use std::ops::Range;
use crate::source::SourceId;
/// A value with the span it corresponds to in the source code.
#[derive(Copy, Clone, Eq, PartialEq, Hash)]
pub struct Spanned<T> {
/// The spanned value.
pub v: T,
/// The location in source code of the value.
pub span: Span,
}
impl<T> Spanned<T> {
/// Create a new instance from a value and its span.
pub fn new(v: T, span: impl Into<Span>) -> Self {
Self { v, span: span.into() }
}
/// Convert from `&Spanned<T>` to `Spanned<&T>`
pub fn as_ref(&self) -> Spanned<&T> {
Spanned { v: &self.v, span: self.span }
}
/// Map the value using a function keeping the span.
pub fn map<F, U>(self, f: F) -> Spanned<U>
where
F: FnOnce(T) -> U,
{
Spanned { v: f(self.v), span: self.span }
}
}
impl<T: Debug> Debug for Spanned<T> {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
self.v.fmt(f)?;
if f.alternate() {
f.write_str(" <")?;
self.span.fmt(f)?;
f.write_str(">")?;
}
Ok(())
}
}
/// Bounds of a slice of source code.
#[derive(Copy, Clone, Eq, PartialEq, Hash)]
pub struct Span {
/// The id of the source file.
pub source: SourceId,
/// The inclusive start position.
pub start: usize,
/// The inclusive end position.
pub end: usize,
}
impl Span {
/// Create a new span from start and end positions.
pub fn new(source: SourceId, start: usize, end: usize) -> Self {
Self { source, start, end }
}
/// Create a span including just a single position.
pub fn at(source: SourceId, pos: usize) -> Self {
Self::new(source, pos, pos)
}
/// Create a span without real location information, usually for testing.
pub fn detached() -> Self {
Self {
source: SourceId::from_raw(0),
start: 0,
end: 0,
}
}
/// Create a span with a different start position.
pub fn with_start(self, start: usize) -> Self {
Self { start, ..self }
}
/// Create a span with a different end position.
pub fn with_end(self, end: usize) -> Self {
Self { end, ..self }
}
/// Whether the span is a single point.
pub fn is_empty(self) -> bool {
self.start == self.end
}
/// The byte length of the spanned region.
pub fn len(self) -> usize {
self.end - self.start
}
/// A new span at the position of this span's start.
pub fn at_start(&self) -> Span {
Self::at(self.source, self.start)
}
/// A new span at the position of this span's end.
pub fn at_end(&self) -> Span {
Self::at(self.source, self.end)
}
/// Create a new span with the earlier start and later end position.
///
/// This panics if the spans come from different files.
pub fn join(self, other: Self) -> Self {
debug_assert_eq!(self.source, other.source);
Self {
source: self.source,
start: self.start.min(other.start),
end: self.end.max(other.end),
}
}
/// Expand a span by merging it with another span.
pub fn expand(&mut self, other: Self) {
*self = self.join(other)
}
/// Test whether a position is within the span.
pub fn contains(&self, pos: usize) -> bool {
self.start <= pos && self.end >= pos
}
/// Test whether one span complete contains the other span.
pub fn surrounds(self, other: Self) -> bool {
self.source == other.source && self.start <= other.start && self.end >= other.end
}
/// Convert to a `Range<usize>` for indexing.
pub fn to_range(self) -> Range<usize> {
self.start .. self.end
}
}
impl Debug for Span {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(f, "{:?}-{:?}", self.start, self.end)
}
}
impl PartialOrd for Span {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
if self.source == other.source {
Some(self.start.cmp(&other.start).then(self.end.cmp(&other.end)))
} else {
None
}
}
}
|
