luna_core/frontend/
error.rs

1//! Syntax-error type produced by the lexer and parser.
2
3use std::fmt;
4
5/// Syntax error, formatted PUC-style: `chunkname:line: msg near 'tok'`.
6/// The `near` part is already baked into `msg` at construction time.
7///
8/// `msg` is a raw byte string — PUC 5.1 reports `near '\xff'`-style errors
9/// with the offending source byte verbatim, and `errors.lua` 5.1 :20 grep-
10/// matches that pattern. Carrying the message as `Vec<u8>` lets the lexer
11/// emit those bytes without UTF-8 enforcement getting in the way.
12#[derive(Clone, PartialEq, Eq, Debug)]
13pub struct SyntaxError {
14    /// 1-based source line where the error was detected. `0` marks a
15    /// message that PUC raises without a position prefix (e.g. 5.4's
16    /// "C stack overflow" while parsing, or a memory error).
17    pub line: u32,
18    /// Message bytes (PUC-style; may contain non-UTF-8 source bytes).
19    pub msg: Vec<u8>,
20}
21
22impl SyntaxError {
23    /// Build a `SyntaxError` at the given line with the given message bytes.
24    pub fn new(line: u32, msg: impl Into<Vec<u8>>) -> Self {
25        SyntaxError {
26            line,
27            msg: msg.into(),
28        }
29    }
30
31    /// An error PUC reports with no `chunk:line:` prefix.
32    pub fn unpositioned(msg: impl Into<Vec<u8>>) -> Self {
33        SyntaxError {
34            line: 0,
35            msg: msg.into(),
36        }
37    }
38
39    /// The complete message as `load` returns it: `<chunkid>:<line>: msg`,
40    /// or the bare message for an unpositioned error. `chunkid` is the
41    /// chunk name already rendered by `luaO_chunkid`.
42    pub fn render(&self, chunkid: &[u8]) -> Vec<u8> {
43        if self.line == 0 {
44            return self.msg.clone();
45        }
46        let mut out = chunkid.to_vec();
47        out.push(b':');
48        out.extend_from_slice(self.line.to_string().as_bytes());
49        out.extend_from_slice(b": ");
50        out.extend_from_slice(&self.msg);
51        out
52    }
53
54    /// Lossy `&str` for Rust-side display (PUC `luaG_addinfo` only cares
55    /// about the bytes; this is for unit tests / panic messages).
56    pub fn msg_str(&self) -> std::borrow::Cow<'_, str> {
57        String::from_utf8_lossy(&self.msg)
58    }
59}
60
61impl fmt::Display for SyntaxError {
62    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
63        if self.line == 0 {
64            return f.write_str(&self.msg_str());
65        }
66        write!(f, "{}: {}", self.line, self.msg_str())
67    }
68}
69
70impl std::error::Error for SyntaxError {}
luna_core/frontend/error.rs

luna_core/frontend/
error.rs
