2021-11-03 16:34:05 +08:00
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//! Define internal parse error types
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//! The goal is to provide a matching and a safe error API, maksing errors from LALR
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use lalrpop_util::ParseError as LalrpopError;
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use crate::ast::Location;
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use crate::token::Tok;
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use std::error::Error;
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use std::fmt;
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/// Represents an error during lexical scanning.
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#[derive(Debug, PartialEq)]
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pub struct LexicalError {
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pub error: LexicalErrorType,
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pub location: Location,
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}
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#[derive(Debug, PartialEq)]
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pub enum LexicalErrorType {
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StringError,
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UnicodeError,
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NestingError,
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IndentationError,
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TabError,
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TabsAfterSpaces,
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DefaultArgumentError,
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PositionalArgumentError,
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DuplicateKeywordArgumentError,
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UnrecognizedToken { tok: char },
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FStringError(FStringErrorType),
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LineContinuationError,
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Eof,
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OtherError(String),
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}
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impl fmt::Display for LexicalErrorType {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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match self {
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LexicalErrorType::StringError => write!(f, "Got unexpected string"),
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LexicalErrorType::FStringError(error) => write!(f, "Got error in f-string: {}", error),
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LexicalErrorType::UnicodeError => write!(f, "Got unexpected unicode"),
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LexicalErrorType::NestingError => write!(f, "Got unexpected nesting"),
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LexicalErrorType::IndentationError => {
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write!(f, "unindent does not match any outer indentation level")
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}
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LexicalErrorType::TabError => {
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write!(f, "inconsistent use of tabs and spaces in indentation")
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}
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LexicalErrorType::TabsAfterSpaces => {
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write!(f, "Tabs not allowed as part of indentation after spaces")
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}
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LexicalErrorType::DefaultArgumentError => {
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write!(f, "non-default argument follows default argument")
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}
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LexicalErrorType::DuplicateKeywordArgumentError => {
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write!(f, "keyword argument repeated")
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}
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LexicalErrorType::PositionalArgumentError => {
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write!(f, "positional argument follows keyword argument")
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}
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LexicalErrorType::UnrecognizedToken { tok } => {
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write!(f, "Got unexpected token {}", tok)
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}
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LexicalErrorType::LineContinuationError => {
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write!(f, "unexpected character after line continuation character")
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}
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LexicalErrorType::Eof => write!(f, "unexpected EOF while parsing"),
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LexicalErrorType::OtherError(msg) => write!(f, "{}", msg),
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}
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}
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}
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// TODO: consolidate these with ParseError
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#[derive(Debug, PartialEq)]
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pub struct FStringError {
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pub error: FStringErrorType,
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pub location: Location,
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}
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#[derive(Debug, PartialEq)]
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pub enum FStringErrorType {
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UnclosedLbrace,
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UnopenedRbrace,
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ExpectedRbrace,
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InvalidExpression(Box<ParseErrorType>),
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InvalidConversionFlag,
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EmptyExpression,
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MismatchedDelimiter,
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ExpressionNestedTooDeeply,
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}
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impl fmt::Display for FStringErrorType {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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match self {
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FStringErrorType::UnclosedLbrace => write!(f, "Unclosed '{{'"),
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FStringErrorType::UnopenedRbrace => write!(f, "Unopened '}}'"),
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FStringErrorType::ExpectedRbrace => write!(f, "Expected '}}' after conversion flag."),
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FStringErrorType::InvalidExpression(error) => {
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write!(f, "Invalid expression: {}", error)
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}
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FStringErrorType::InvalidConversionFlag => write!(f, "Invalid conversion flag"),
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FStringErrorType::EmptyExpression => write!(f, "Empty expression"),
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FStringErrorType::MismatchedDelimiter => write!(f, "Mismatched delimiter"),
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FStringErrorType::ExpressionNestedTooDeeply => {
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write!(f, "expressions nested too deeply")
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}
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}
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}
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}
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impl From<FStringError> for LalrpopError<Location, Tok, LexicalError> {
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fn from(err: FStringError) -> Self {
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lalrpop_util::ParseError::User {
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error: LexicalError {
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error: LexicalErrorType::FStringError(err.error),
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location: err.location,
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},
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}
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}
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}
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/// Represents an error during parsing
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#[derive(Debug, PartialEq)]
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pub struct ParseError {
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pub error: ParseErrorType,
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pub location: Location,
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}
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#[derive(Debug, PartialEq)]
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pub enum ParseErrorType {
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/// Parser encountered an unexpected end of input
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Eof,
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/// Parser encountered an extra token
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ExtraToken(Tok),
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/// Parser encountered an invalid token
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InvalidToken,
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/// Parser encountered an unexpected token
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UnrecognizedToken(Tok, Option<String>),
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/// Maps to `User` type from `lalrpop-util`
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Lexical(LexicalErrorType),
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}
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/// Convert `lalrpop_util::ParseError` to our internal type
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impl From<LalrpopError<Location, Tok, LexicalError>> for ParseError {
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fn from(err: LalrpopError<Location, Tok, LexicalError>) -> Self {
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match err {
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// TODO: Are there cases where this isn't an EOF?
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LalrpopError::InvalidToken { location } => ParseError {
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error: ParseErrorType::Eof,
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location,
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},
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LalrpopError::ExtraToken { token } => ParseError {
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error: ParseErrorType::ExtraToken(token.1),
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location: token.0,
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},
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LalrpopError::User { error } => ParseError {
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error: ParseErrorType::Lexical(error.error),
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location: error.location,
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},
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LalrpopError::UnrecognizedToken { token, expected } => {
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// Hacky, but it's how CPython does it. See PyParser_AddToken,
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// in particular "Only one possible expected token" comment.
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let expected = if expected.len() == 1 {
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Some(expected[0].clone())
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} else {
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None
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};
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ParseError {
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error: ParseErrorType::UnrecognizedToken(token.1, expected),
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location: token.0,
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}
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}
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2023-09-01 16:56:32 +08:00
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LalrpopError::UnrecognizedEof { location, .. } => ParseError {
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2021-11-03 16:34:05 +08:00
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error: ParseErrorType::Eof,
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location,
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},
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}
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}
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}
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impl fmt::Display for ParseError {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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write!(f, "{} at {}", self.error, self.location)
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}
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}
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impl fmt::Display for ParseErrorType {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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match *self {
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ParseErrorType::Eof => write!(f, "Got unexpected EOF"),
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ParseErrorType::ExtraToken(ref tok) => write!(f, "Got extraneous token: {:?}", tok),
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ParseErrorType::InvalidToken => write!(f, "Got invalid token"),
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ParseErrorType::UnrecognizedToken(ref tok, ref expected) => {
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if *tok == Tok::Indent {
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write!(f, "unexpected indent")
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} else if expected.as_deref() == Some("Indent") {
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write!(f, "expected an indented block")
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} else {
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write!(f, "Got unexpected token {}", tok)
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}
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}
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ParseErrorType::Lexical(ref error) => write!(f, "{}", error),
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}
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}
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}
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impl Error for ParseErrorType {}
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impl ParseErrorType {
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pub fn is_indentation_error(&self) -> bool {
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match self {
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ParseErrorType::Lexical(LexicalErrorType::IndentationError) => true,
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ParseErrorType::UnrecognizedToken(token, expected) => {
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*token == Tok::Indent || expected.clone() == Some("Indent".to_owned())
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}
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_ => false,
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}
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}
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pub fn is_tab_error(&self) -> bool {
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matches!(
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self,
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ParseErrorType::Lexical(LexicalErrorType::TabError)
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| ParseErrorType::Lexical(LexicalErrorType::TabsAfterSpaces)
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)
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}
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}
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impl std::ops::Deref for ParseError {
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type Target = ParseErrorType;
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fn deref(&self) -> &Self::Target {
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&self.error
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}
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}
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impl Error for ParseError {
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fn source(&self) -> Option<&(dyn Error + 'static)> {
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None
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}
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}
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