Files
ngr/src/errors.rs

115 lines
4.2 KiB
Rust

use crate::syntax::{Location, ParserError};
use codespan_reporting::diagnostic::Diagnostic;
use codespan_reporting::files;
use std::io;
#[derive(Debug)]
pub enum Error {
IOError(io::Error),
InternalFileDBError(files::Error),
ParserError(ParserError),
BindingSiteFailure(Location, String),
UnboundVariable(Location, String),
InternalError(Location, String),
}
fn display_expected(expected: &[String]) -> String {
match expected.len() {
0 => "".to_string(),
1 => format!("; expected {}", expected[0]),
2 => format!("; expected {} or {}", expected[0], expected[1]),
n => format!(
"; expected {}or {}",
comma_separate(&expected[0..n - 1]),
expected[n - 1]
),
}
}
fn comma_separate(strings: &[String]) -> String {
let mut result = String::new();
for s in strings.iter() {
result.push_str(s);
result.push_str(", ");
}
result
}
impl From<Error> for Diagnostic<usize> {
fn from(x: Error) -> Self {
match &x {
Error::IOError(e) => Diagnostic::error().with_message(format!("{}", e)),
Error::InternalFileDBError(e) => Diagnostic::error().with_message(format!("{}", e)),
Error::ParserError(pe) => match pe {
// this was just a token we didn't understand
ParserError::InvalidToken(location) => location
.labelled_error("extremely odd token")
.with_message("encountered extremely confusing token"),
// unexpected EOF!
ParserError::UnrecognizedEOF(location, expected) => location.error().with_message(
format!("expected enf of file{}", display_expected(expected)),
),
// encountered a token where it shouldn't be
ParserError::UnrecognizedToken(start, end, token, expected) => {
let expected_str =
format!("unexpected token {}{}", token, display_expected(expected));
let unexpected_str = format!("unexpected token {}", token);
let mut labels = start.range_label(end);
Diagnostic::error()
.with_labels(
labels
.drain(..)
.map(|l| l.with_message(unexpected_str.clone()))
.collect(),
)
.with_message(expected_str)
}
// I think we get this when we get a token, but were expected EOF
ParserError::ExtraToken(start, token, end) => {
let expected_str =
format!("unexpected token {} after the expected end of file", token);
let unexpected_str = format!("unexpected token {}", token);
let mut labels = start.range_label(end);
Diagnostic::error()
.with_labels(
labels
.drain(..)
.map(|l| l.with_message(unexpected_str.clone()))
.collect(),
)
.with_message(expected_str)
}
// simple lexer errors
ParserError::LexFailure(location) => {
location.error().with_message("unexpected character")
}
},
Error::BindingSiteFailure(location, name) => location
.labelled_error("discovered here")
.with_message(format!(
"Internal Error: Lost binding site for bound variable {}",
name
)),
Error::UnboundVariable(location, name) => location
.labelled_error("unbound here")
.with_message(format!("Unbound variable '{}'", name)),
Error::InternalError(location, string) => location
.labelled_error("this is related")
.with_message(format!("Internal error: {}", string)),
}
}
}