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use serde::*;
use std::{
fmt,
ops::{Bound, RangeBounds},
};
/// A struct to define the context of an error message
#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Hash)]
pub enum Context {
/// When no context can be given
None,
/// When only a line (e.g. in a file) can be shown
Show {
/// The line to be shown to the user (e.g. filename)
line: String,
},
/// When a full line is faulty and no special position can be annotated
FullLine {
/// The line number to recognise where the error is located
line_index: usize,
/// The line to show the issue itself
line: String,
},
/// When a special position can be annotated on a line.
/// ```text
/// |
/// 104 | ATOM O N MET A 1 27.251 24.447 2.594 1.00 11.79 N
/// | ^^^^
/// <- -><-->
/// ```
/// The first space (annotated by `<-`, `->`) is the offset, in this case 7. The
/// second space is the length, in this case 4.
Line {
/// The line index to recognise where the error is located.
line_index: Option<usize>,
/// The line to show the issue itself.
line: String,
/// The offset of the special position to be annotated.
offset: usize,
/// The length of the special position to be annotated.
length: usize,
},
/// To show multiple lines where an error occurred.
Range {
/// The index of the first line
start_line_index: usize,
/// The lines to show
lines: Vec<String>,
/// The possible offset of the first line, will be padded with spaces
offset: usize,
},
/// To show multiple lines where an error occurred.
RangeHighlights {
/// The index of the first line
start_line_index: usize,
/// The lines to show
lines: Vec<String>,
/// Highlights defined by the line (relative to the set of lines given), start column in that line and length of highlight
highlights: Vec<(usize, usize, usize)>,
},
/// To show multiple contexts
Multiple {
/// The contexts to show
contexts: Vec<(Option<String>, Context)>,
},
}
#[expect(clippy::needless_pass_by_value)] // the impl ToString should be passed like this, otherwise &str gives errors
impl Context {
/// Creates a new context when no context can be given
pub const fn none() -> Self {
Self::None
}
/// Creates a new context when only a line (eg filename) can be shown
pub fn show(line: impl std::string::ToString) -> Self {
Self::Show {
line: line.to_string().replace('\t', " "),
}
}
/// Creates a new context when a full line is faulty and no special position can be annotated
pub fn full_line(line_index: usize, line: impl std::string::ToString) -> Self {
Self::FullLine {
line_index,
line: line.to_string().replace('\t', " "),
}
}
/// Creates a new context when a special position can be annotated on a line
pub fn line(
line_index: Option<usize>,
line: impl std::string::ToString,
offset: usize,
length: usize,
) -> Self {
Self::Line {
line_index,
line: line.to_string().replace('\t', " "),
offset,
length,
}
}
/// Create a context highlighting a certain range on a single line
pub fn line_range(
line_index: Option<usize>,
line: impl std::string::ToString,
range: impl RangeBounds<usize>,
) -> Self {
let line = line.to_string();
match (range.start_bound(), range.end_bound()) {
(Bound::Unbounded, Bound::Unbounded) => {
line_index.map_or_else(|| Self::show(&line), |i| Self::full_line(i, &line))
}
(start, end) => {
let start = match start {
Bound::Excluded(n) => n + 1,
Bound::Included(n) => *n,
Bound::Unbounded => 0,
};
Self::line(
line_index,
&line,
start,
match end {
Bound::Excluded(n) => n - 1,
Bound::Included(n) => *n,
Bound::Unbounded => line.chars().count(),
}
.saturating_sub(start),
)
}
}
}
/// Creates a new context to highlight a certain position
#[expect(clippy::unwrap_used, clippy::missing_panics_doc)]
pub fn position(pos: &FilePosition<'_>) -> Self {
if pos.text.is_empty() {
Self::Line {
line_index: Some(pos.line_index),
line: String::new(),
offset: 0,
length: 3,
}
} else {
Self::Line {
line_index: Some(pos.line_index),
line: pos
.text
.lines()
.next()
.unwrap()
.to_string()
.replace('\t', " "),
offset: 0,
length: 3,
}
}
}
/// Creates a new context from a start and end point within a single file
pub fn range(start: &FilePosition<'_>, end: &FilePosition<'_>) -> Self {
if start.line_index == end.line_index {
Self::Line {
line_index: Some(start.line_index),
line: start.text[..(end.column - start.column)].to_string(),
offset: start.column,
length: end.column - start.column,
}
} else {
Self::Range {
start_line_index: start.line_index,
lines: start
.text
.lines()
.take(end.line_index - start.line_index)
.map(ToString::to_string)
.collect::<Vec<String>>(),
offset: start.column,
}
}
}
/// Overwrite the line number with the given number, if applicable
#[must_use]
pub fn overwrite_line_number(self, line_index: usize) -> Self {
match self {
Self::FullLine { line, .. } => Self::FullLine { line_index, line },
Self::Line {
line,
offset,
length,
..
} => Self::Line {
line_index: Some(line_index),
line,
offset,
length,
},
Self::Range { lines, offset, .. } => Self::Range {
start_line_index: line_index,
offset,
lines,
},
Self::RangeHighlights {
lines, highlights, ..
} => Self::RangeHighlights {
start_line_index: line_index,
lines,
highlights,
},
Self::Multiple { contexts } => Self::Multiple {
contexts: contexts
.into_iter()
.map(|(l, c)| (l, c.overwrite_line_number(line_index)))
.collect(),
},
n => n,
}
}
/// Display this context, with an optional note after the context.
/// # Errors
/// If the underlying formatter errors.
fn display(&self, f: &mut fmt::Formatter<'_>, note: Option<&str>) -> fmt::Result {
const MAX_COLS: usize = 95;
let mut tail = true; // End with a tailing line ╵
#[expect(
clippy::cast_sign_loss,
clippy::cast_precision_loss,
clippy::cast_possible_truncation
)]
let get_margin = |n| ((n + 1) as f64).log10().max(1.0).ceil() as usize;
let margin = match self {
Self::None | Self::Multiple { .. } => 0,
Self::Show { .. } => 2,
Self::FullLine { line_index: n, .. } => get_margin(*n),
Self::Line { line_index: n, .. } => n.map_or(0, get_margin),
Self::Range {
start_line_index: n,
lines: l,
..
}
| Self::RangeHighlights {
start_line_index: n,
lines: l,
..
} => get_margin(n + l.len()),
};
match self {
Self::None => {
return Ok(());
}
Self::Show { line } => {
write!(f, "\n{:pad$} ╷\n{:pad$} │ {}", "", "", line, pad = margin)?;
}
Self::FullLine { line_index, line } => write!(
f,
"\n{:pad$} ╷\n{:<pad$} │ {}",
"",
line_index + 1,
line,
pad = margin
)?,
Self::Line {
line_index,
line,
offset,
length,
} => {
let (start, end) = if line.len() > MAX_COLS {
let pad = MAX_COLS.saturating_sub(*length) / 2;
let mut start = offset.saturating_sub(pad).min(line.len());
while !line.is_char_boundary(start) {
start -= 1;
}
let mut end = (start + MAX_COLS).min(line.len());
while !line.is_char_boundary(end) {
end += 1;
}
(start, end)
} else {
(0, line.len())
};
write!(
f,
"\n{:pad$} ╷\n{:<pad$} │ {}{}{}\n{:pad$} · {}{}",
"",
line_index.map_or(String::new(), |n| (n + 1).to_string()),
if start == 0 { "" } else { "…" },
&line[start..end],
if end == line.len() { "" } else { "…" },
"",
" ".repeat(*offset - start + usize::from(start != 0)),
if *length == 0 {
"└".to_string()
} else {
"‾".repeat(*length)
},
pad = margin
)?;
}
Self::Range {
start_line_index,
lines,
offset,
} => {
write!(f, "\n{:pad$} ╷", "", pad = margin)?;
let mut number = *start_line_index + 1;
write!(
f,
"\n{:<pad$} │ {}{}",
number,
" ".repeat(*offset),
lines[0],
pad = margin
)?;
for line in lines.iter().skip(1) {
number += 1;
write!(f, "\n{number:<margin$} │ {line}")?;
}
}
Self::RangeHighlights {
start_line_index: start_linenumber,
lines,
highlights,
} => {
write!(f, "\n{:pad$} ╷", "", pad = margin)?;
let mut number = *start_linenumber + 1;
let mut highlights_peek = highlights.iter().peekable();
for (index, line) in lines.iter().enumerate() {
number += 1;
write!(f, "\n{number:<margin$} │ {line}")?;
let mut first = true;
let mut last_offset = 0;
while let Some(high) = highlights_peek.peek() {
if high.0 > index {
break;
}
if let Some(high) = highlights_peek.next() {
if first {
write!(f, "\n{:pad$} · ", "", pad = margin)?;
first = false;
}
if last_offset < high.1 {
write!(
f,
"{}{}",
" ".repeat(high.1 - last_offset),
"‾".repeat(high.2)
)?;
last_offset = high.1 + high.2;
} else {
eprintln!("A highlight in a range error message is detected to overlap with a previous highlight, it is skipped.");
// Panicking on error gave the following very intense error message (in test code):
// `thread panicked while panicking. aborting. ... (exit code: 0xc000001d, STATUS_ILLEGAL_INSTRUCTION)`
// To prevent other people from panicking upon seeing this error message this error is not raised currently.
}
}
}
}
}
Self::Multiple { contexts } => {
for (note, context) in contexts {
context.display(f, note.as_deref())?;
}
tail = false;
}
}
// Last line
if let Some(note) = note {
write!(f, "\n{:pad$} ╰{}", "", note, pad = margin)
} else if tail {
write!(f, "\n{:pad$} ╵", "", pad = margin)
} else {
Ok(())
}
}
}
impl fmt::Display for Context {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.display(f, None)
}
}
#[derive(Debug, Eq, PartialEq, Copy, Clone)]
/// A position in a file for use in parsing/lexing
pub struct FilePosition<'a> {
/// The remaining text (as ref so no copies)
pub text: &'a str,
/// The current line index
pub line_index: usize,
/// The current column number
pub column: usize,
}