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use std::fs;
use std::ops::Range;
use crate::{GrammarAnalysisError, ParolParserError};
use parol_runtime::{
Report,
codespan_reporting::{
diagnostic::{Diagnostic, Label},
files::SimpleFiles,
term::{self, Config, termcolor::StandardStream},
},
};
/// Error reporter for user errors generated by the parol parser itself.
pub struct ParolErrorReporter {}
impl Report for ParolErrorReporter {
fn report_user_error(err: &anyhow::Error) -> anyhow::Result<()> {
let files: SimpleFiles<String, String> = SimpleFiles::new();
let mut writer = StandardStream::stderr(term::termcolor::ColorChoice::Auto);
let config = Config::default();
if let Some(err) = err.downcast_ref::<ParolParserError>() {
match err {
ParolParserError::UnknownScanner {
context,
name,
input,
token,
} => {
let mut files = SimpleFiles::new();
let content = fs::read_to_string(input).unwrap_or_default();
let file_id = files.add(input.display().to_string(), content);
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message(format!("{context} - Unknown scanner {name}"))
.with_code("parol::parser::unknown_scanner")
.with_labels(vec![Label::primary(file_id, Into::<Range<usize>>::into(token))])
.with_notes(vec!["Undeclared scanner found. Please declare a scanner via %scanner name {{...}}".to_string()])
)?)
}
ParolParserError::EmptyGroup {
context,
input,
start,
end,
} => {
let mut files = SimpleFiles::new();
let content = fs::read_to_string(input).unwrap_or_default();
let file_id = files.add(input.display().to_string(), content);
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message(format!("{context} - Empty Group not allowed"))
.with_code("parol::parser::empty_group")
.with_labels(vec![
Label::primary(file_id, Into::<Range<usize>>::into(start))
.with_message("Start"),
Label::primary(file_id, Into::<Range<usize>>::into(end))
.with_message("End"),
])
.with_notes(vec!["Empty groups can be safely removed.".to_string()]),
)?)
}
ParolParserError::EmptyOptional {
context,
input,
start,
end,
} => {
let mut files = SimpleFiles::new();
let content = fs::read_to_string(input).unwrap_or_default();
let file_id = files.add(input.display().to_string(), content);
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message(format!("{context} - Empty Optionals not allowed"))
.with_code("parol::parser::empty_optional")
.with_labels(vec![
Label::primary(file_id, Into::<Range<usize>>::into(start))
.with_message("Start"),
Label::primary(file_id, Into::<Range<usize>>::into(end))
.with_message("End"),
])
.with_notes(vec!["Empty optionals can be safely removed.".to_string()]),
)?)
}
ParolParserError::EmptyRepetition {
context,
input,
start,
end,
} => {
let mut files = SimpleFiles::new();
let content = fs::read_to_string(input).unwrap_or_default();
let file_id = files.add(input.display().to_string(), content);
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message(format!("{context} - Empty Repetitions not allowed"))
.with_code("parol::parser::empty_repetition")
.with_labels(vec![
Label::primary(file_id, Into::<Range<usize>>::into(start))
.with_message("Start"),
Label::primary(file_id, Into::<Range<usize>>::into(end))
.with_message("End"),
])
.with_notes(vec![
"Empty repetitions can be safely removed.".to_string(),
]),
)?)
}
ParolParserError::ConflictingTokenAliases {
first_alias,
second_alias,
expanded,
input,
first,
second,
} => {
let mut files = SimpleFiles::new();
let content = fs::read_to_string(input).unwrap_or_default();
let file_id = files.add(input.display().to_string(), content);
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message(format!(
r"Multiple token aliases that expand to the same text:
'{first_alias}' and '{second_alias}' expand both to '{expanded}'."
))
.with_code("parol::parser::conflicting_token_aliases")
.with_labels(vec![
Label::primary(file_id, Into::<Range<usize>>::into(first))
.with_message("First alias"),
Label::primary(file_id, Into::<Range<usize>>::into(second))
.with_message("Second alias"),
])
.with_notes(vec![
"Consider using only one single terminal instead of two."
.to_string(),
]),
)?)
}
ParolParserError::EmptyScanners { empty_scanners } => {
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message(format!(
"Empty scanner states ({empty_scanners:?}) found"
))
.with_code("parol::parser::empty_scanner_states")
.with_notes(vec![
"Assign at least one terminal or remove them.".to_string(),
]),
)?)
}
ParolParserError::UnsupportedGrammarType {
grammar_type,
input,
token,
} => {
let mut files = SimpleFiles::new();
let content = fs::read_to_string(input).unwrap_or_default();
let file_id = files.add(input.display().to_string(), content);
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message(format!("{grammar_type} - Unsupported grammar type"))
.with_code("parol::parser::unsupported_grammar_type")
.with_labels(vec![Label::primary(
file_id,
Into::<Range<usize>>::into(token),
)])
.with_notes(vec![
"Only 'LL(k)' and 'LALR(1)' are supported. Use RawString literals here.".to_string()
]),
)?)
}
ParolParserError::UnsupportedFeature {
feature,
hint,
input,
token,
} => {
let mut files = SimpleFiles::new();
let content = fs::read_to_string(input).unwrap_or_default();
let file_id = files.add(input.display().to_string(), content);
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message(format!("{feature} - Unsupported feature"))
.with_code("parol::parser::unsupported_feature")
.with_labels(vec![Label::primary(
file_id,
Into::<Range<usize>>::into(token),
)])
.with_notes(vec![
"This feature is not supported.".to_string(),
hint.to_string(),
]),
)?)
}
ParolParserError::InvalidTokenInTransition {
context,
token,
input,
location,
} => {
let mut files = SimpleFiles::new();
let content = fs::read_to_string(input).unwrap_or_default();
let file_id = files.add(input.display().to_string(), content);
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message(format!(
"{context} - Invalid token '{token}' in transition. Use a primary non-terminal for the token."
))
.with_code("parol::parser::invalid_token_in_transition")
.with_labels(vec![Label::primary(
file_id,
Into::<Range<usize>>::into(location),
)])
.with_notes(vec![
"Please use a primary non-terminal for the token.".to_string()
]),
)?)
}
ParolParserError::TokenIsNotInScanner {
context,
scanner,
token,
input,
location,
} => {
let mut files = SimpleFiles::new();
let content = fs::read_to_string(input).unwrap_or_default();
let file_id = files.add(input.display().to_string(), content);
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message(format!(
"{context} - Token '{token}' is not defined in scanner '{scanner}'"
))
.with_code("parol::parser::token_is_not_in_scanner")
.with_labels(vec![Label::primary(
file_id,
Into::<Range<usize>>::into(location),
)])
.with_notes(vec![
"Only tokens used in a scanner can initiate a transition from it to another scanner."
.to_string(),
]),
)?)
}
_ => {
unreachable!(
"Scanner switching directives have been removed from the grammar syntax."
);
}
}
} else if let Some(err) = err.downcast_ref::<GrammarAnalysisError>() {
match err {
GrammarAnalysisError::LeftRecursion { recursions } => {
let non_terminals = recursions
.iter()
.map(|r| r.name.to_string())
.collect::<Vec<String>>()
.join(", ");
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message("Grammar contains left-recursions")
.with_code("parol::analysis::left_recursion")
.with_notes(vec![
"Left-recursions detected.".to_string(),
non_terminals,
"Please rework your grammar to remove these recursions."
.to_string(),
]),
)?)
}
GrammarAnalysisError::UnreachableNonTerminals { non_terminals } => {
let non_terminals = non_terminals
.iter()
.map(|r| r.hint.clone())
.collect::<Vec<String>>()
.join(", ");
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message("Grammar contains unreachable non-terminals")
.with_code("parol::analysis::unreachable_non_terminals")
.with_notes(vec![
"Non-terminals:".to_string(),
non_terminals,
"Unreachable non-terminals are not allowed. If not used they can be safely removed.".to_string(),
]),
)?)
}
GrammarAnalysisError::NonProductiveNonTerminals { non_terminals } => {
let non_terminals = non_terminals
.iter()
.map(|r| r.hint.clone())
.collect::<Vec<String>>()
.join(", ");
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message("Grammar contains nonproductive non-terminals")
.with_code("parol::analysis::nonproductive_non_terminals")
.with_notes(vec![
"Non-terminals:".to_string(),
non_terminals,
"Nonproductive non-terminals are not allowed. If not used they can be safely removed.".to_string(),
]),
)?)
}
GrammarAnalysisError::MaxKExceeded { max_k } => Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message(format!("Maximum lookahead of {max_k} exceeded"))
.with_code("parol::analysis::max_k_exceeded")
.with_notes(vec!["Please examine your grammar.".to_string()]),
)?),
GrammarAnalysisError::LALR1ParseTableConstructionFailed { conflict } => {
Ok(term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message("LALR(1) parse table construction failed with conflicts")
.with_code("parol::analysis::lalr1_parse_table_construction_failed")
.with_notes(vec![
"Please examine your grammar.".to_string(),
format!("{}", conflict),
]),
)?)
}
}
} else {
let result = term::emit_to_write_style(
&mut writer,
&config,
&files,
&Diagnostic::error()
.with_message("Parol error")
.with_notes(vec![
err.to_string(),
err.source()
.map_or("No details".to_string(), |s| s.to_string()),
]),
);
result.map_err(|e| anyhow::anyhow!(e))
}
}
}