antlr4_runtime/
errors.rs

1use crate::recognizer::Recognizer;
2use thiserror::Error;
3
4#[derive(Debug, Error, Clone, Eq, PartialEq)]
5pub enum AntlrError {
6    #[error("mismatched input: expected {expected}, found {found}")]
7    MismatchedInput { expected: String, found: String },
8    #[error("no viable alternative at input {input}")]
9    NoViableAlternative { input: String },
10    #[error("lexer error at {line}:{column}: {message}")]
11    LexerError {
12        line: usize,
13        column: usize,
14        message: String,
15    },
16    #[error("parser error at {line}:{column}: {message}")]
17    ParserError {
18        line: usize,
19        column: usize,
20        message: String,
21    },
22    #[error("unsupported runtime feature: {0}")]
23    Unsupported(String),
24}
25
26/// Receives recognizer diagnostics.
27///
28/// Listeners registered through [`Recognizer::add_error_listener`] must be
29/// [`Send`] and work with every recognizer type. Implement the trait
30/// generically, as [`ConsoleErrorListener`] does, when a listener will be
31/// registered.
32pub trait ErrorListener<R: Recognizer + ?Sized> {
33    fn syntax_error(
34        &mut self,
35        recognizer: &R,
36        line: usize,
37        column: usize,
38        message: &str,
39        error: Option<&AntlrError>,
40    );
41}
42
43#[derive(Debug, Default)]
44pub struct ConsoleErrorListener;
45
46impl<R: Recognizer + ?Sized> ErrorListener<R> for ConsoleErrorListener {
47    #[allow(clippy::print_stderr)]
48    fn syntax_error(
49        &mut self,
50        _recognizer: &R,
51        line: usize,
52        column: usize,
53        message: &str,
54        _error: Option<&AntlrError>,
55    ) {
56        eprintln!("line {line}:{column} {message}");
57    }
58}
antlr4_runtime/errors.rs

antlr4_runtime/
errors.rs
