use std::fmt;
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy)]
pub struct SourcePosition {
index: usize,
line: usize,
col: usize,
}
#[derive(Debug, Clone, PartialEq, Eq, Hash, Copy)]
pub struct Spanning<T> {
pub item: T,
pub start: SourcePosition,
pub end: SourcePosition,
}
impl<T> Spanning<T> {
#[doc(hidden)]
pub fn zero_width(pos: &SourcePosition, item: T) -> Spanning<T> {
Spanning {
item,
start: *pos,
end: *pos,
}
}
#[doc(hidden)]
pub fn single_width(pos: &SourcePosition, item: T) -> Spanning<T> {
let mut end = *pos;
end.advance_col();
Spanning {
item,
start: *pos,
end,
}
}
#[doc(hidden)]
pub fn start_end(start: &SourcePosition, end: &SourcePosition, item: T) -> Spanning<T> {
Spanning {
item,
start: *start,
end: *end,
}
}
#[doc(hidden)]
#[allow(clippy::self_named_constructors)]
pub fn spanning(v: Vec<Spanning<T>>) -> Option<Spanning<Vec<Spanning<T>>>> {
if let (Some(start), Some(end)) = (v.first().map(|s| s.start), v.last().map(|s| s.end)) {
Some(Spanning {
item: v,
start,
end,
})
} else {
None
}
}
#[doc(hidden)]
pub fn unlocated(item: T) -> Spanning<T> {
Spanning {
item,
start: SourcePosition::new_origin(),
end: SourcePosition::new_origin(),
}
}
pub fn map<O, F: Fn(T) -> O>(self, f: F) -> Spanning<O> {
Spanning {
item: f(self.item),
start: self.start,
end: self.end,
}
}
pub fn and_then<O, F: Fn(T) -> Option<O>>(self, f: F) -> Option<Spanning<O>> {
let (start, end) = (self.start, self.end);
f(self.item).map(|item| Spanning { item, start, end })
}
}
impl<T: fmt::Display> fmt::Display for Spanning<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}. At {}", self.item, self.start)
}
}
impl<T: std::error::Error> std::error::Error for Spanning<T> {}
impl SourcePosition {
#[doc(hidden)]
pub fn new(index: usize, line: usize, col: usize) -> SourcePosition {
assert!(index >= line + col);
SourcePosition { index, line, col }
}
#[doc(hidden)]
pub fn new_origin() -> SourcePosition {
SourcePosition {
index: 0,
line: 0,
col: 0,
}
}
#[doc(hidden)]
pub fn advance_col(&mut self) {
self.index += 1;
self.col += 1;
}
#[doc(hidden)]
pub fn advance_line(&mut self) {
self.index += 1;
self.line += 1;
self.col = 0;
}
pub fn index(&self) -> usize {
self.index
}
pub fn line(&self) -> usize {
self.line
}
pub fn column(&self) -> usize {
self.col
}
}
impl fmt::Display for SourcePosition {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}:{}", self.line, self.col)
}
}