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fix: parser error recovery #1730

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fix: parser error recovery #1730

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1,221 changes: 1,221 additions & 0 deletions docs/parser-recovery.md
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39 changes: 30 additions & 9 deletions src/lexer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@ macro_rules! expect_token {
($lexer:expr, $token:expr, $return_value:expr) => {
if $lexer.token != $token {
$lexer.accept_diagnostic(Diagnostic::unexpected_token_found(
format!("{:?}", $token).as_str(),
$token.to_string().as_str(),
$lexer.slice(),
$lexer.location(),
));
Expand Down Expand Up @@ -82,7 +82,7 @@ impl<'a> ParseSession<'a> {

pub fn try_consume_or_report(&mut self, token: Token) {
if !self.try_consume(token) {
self.accept_diagnostic(Diagnostic::missing_token(format!("{token:?}").as_str(), self.location()));
self.accept_diagnostic(Diagnostic::missing_token(token.to_string().as_str(), self.location()));
}
}

Expand Down Expand Up @@ -143,6 +143,26 @@ impl<'a> ParseSession<'a> {
self.lexer.slice()
}

pub fn peek_token(&self) -> Token {
let mut lexer = self.lexer.clone();
lexer.next().unwrap_or(Token::End)
}

pub fn token_appears_before(&self, needle: Token, boundaries: &[Token]) -> bool {
let mut lexer = self.lexer.clone();
while let Some(token) = lexer.next() {
if token == needle {
return true;
}

if boundaries.contains(&token) {
return false;
}
}

false
}

pub fn location(&self) -> SourceLocation {
self.source_range_factory.create_range(self.range())
}
Expand All @@ -167,7 +187,7 @@ impl<'a> ParseSession<'a> {
if let Some(expected_token) = self.closing_keywords.pop() {
if !expected_token.contains(&self.token) {
self.accept_diagnostic(Diagnostic::unexpected_token_found(
format!("{:?}", expected_token[0]).as_str(),
expected_token[0].to_string().as_str(),
format!("'{}'", self.slice()).as_str(),
self.location(),
));
Expand Down Expand Up @@ -202,11 +222,12 @@ impl<'a> ParseSession<'a> {
if start.end != self.range().end {
let range = start.start..end;
self.accept_diagnostic(Diagnostic::unexpected_token_found(
format!(
"{:?}",
self.closing_keywords.last().and_then(|it| it.first()).unwrap_or(&Token::End) //only show first expected token
)
.as_str(),
self.closing_keywords
.last()
.and_then(|it| it.first())
.unwrap_or(&Token::End)
.to_string()
.as_str(),
format!("'{}'", self.slice_region(range.clone())).as_str(),
self.source_range_factory.create_range(range),
));
Expand All @@ -218,7 +239,7 @@ impl<'a> ParseSession<'a> {
.closing_keywords
.last()
.expect("parse-recovery has no closing-keyword to recover from."); //illegal state! invalid use of parser-recovery?
let expected_tokens = format!("{closing:?}");
let expected_tokens = Token::display_list(closing);
self.accept_diagnostic(Diagnostic::missing_token(expected_tokens.as_str(), self.location()));
}
}
Expand Down
150 changes: 150 additions & 0 deletions src/lexer/tokens.rs
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Original file line number Diff line number Diff line change
@@ -1,3 +1,5 @@
use std::fmt;

use logos::Logos;

use plc_ast::ast::{DirectAccessType, HardwareAccessType};
Expand Down Expand Up @@ -440,6 +442,14 @@ pub enum Token {
}

impl Token {
pub fn display_list(tokens: &[Token]) -> String {
match tokens {
[] => "end of file".into(),
[token] => token.to_string(),
tokens => tokens.iter().map(ToString::to_string).collect::<Vec<_>>().join(" or "),
}
}

/// Returns true if the current token represents any `VAR(_*)` keyword
pub fn is_var(&self) -> bool {
matches!(
Expand All @@ -460,3 +470,143 @@ impl Token {
matches!(self, Token::Identifier | Token::KeywordPropertyGet | Token::KeywordPropertySet)
}
}

impl fmt::Display for Token {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Token::Error => write!(f, "unknown token"),
Token::PropertyExternal => write!(f, "`@EXTERNAL`"),
Token::PropertyByRef => write!(f, "`{{ref}}`"),
Token::PropertyConstant => write!(f, "`@CONSTANT`"),
Token::PropertySized => write!(f, "`{{sized}}`"),
Token::KeywordProgram => write!(f, "`PROGRAM`"),
Token::KeywordClass => write!(f, "`CLASS`"),
Token::KeywordEndClass => write!(f, "`END_CLASS`"),
Token::KeywordExtends => write!(f, "`EXTENDS`"),
Token::KeywordImplements => write!(f, "`IMPLEMENTS`"),
Token::KeywordInterface => write!(f, "`INTERFACE`"),
Token::KeywordEndInterface => write!(f, "`END_INTERFACE`"),
Token::KeywordVarInput => write!(f, "`VAR_INPUT`"),
Token::KeywordVarOutput => write!(f, "`VAR_OUTPUT`"),
Token::KeywordVar => write!(f, "`VAR`"),
Token::KeywordVarConfig => write!(f, "`VAR_CONFIG`"),
Token::KeywordAbstract => write!(f, "`ABSTRACT`"),
Token::KeywordFinal => write!(f, "`FINAL`"),
Token::KeywordMethod => write!(f, "`METHOD`"),
Token::KeywordEndMethod => write!(f, "`END_METHOD`"),
Token::KeywordSuper => write!(f, "`SUPER`"),
Token::KeywordThis => write!(f, "`THIS`"),
Token::KeywordPropertyGet => write!(f, "`PROPERTY_GET`"),
Token::KeywordPropertySet => write!(f, "`PROPERTY_SET`"),
Token::KeywordEndProperty => write!(f, "`END_PROPERTY`"),
Token::KeywordConstant => write!(f, "`CONSTANT`"),
Token::KeywordRetain => write!(f, "`RETAIN`"),
Token::KeywordNonRetain => write!(f, "`NON_RETAIN`"),
Token::KeywordVarTemp => write!(f, "`VAR_TEMP`"),
Token::KeywordAccessPublic => write!(f, "`PUBLIC`"),
Token::KeywordAccessPrivate => write!(f, "`PRIVATE`"),
Token::KeywordAccessInternal => write!(f, "`INTERNAL`"),
Token::KeywordAccessProtected => write!(f, "`PROTECTED`"),
Token::KeywordOverride => write!(f, "`OVERRIDE`"),
Token::KeywordVarGlobal => write!(f, "`VAR_GLOBAL`"),
Token::KeywordVarInOut => write!(f, "`VAR_IN_OUT`"),
Token::KeywordVarExternal => write!(f, "`VAR_EXTERNAL`"),
Token::KeywordEndVar => write!(f, "`END_VAR`"),
Token::KeywordEndProgram => write!(f, "`END_PROGRAM`"),
Token::KeywordFunction => write!(f, "`FUNCTION`"),
Token::KeywordEndFunction => write!(f, "`END_FUNCTION`"),
Token::KeywordFunctionBlock => write!(f, "`FUNCTION_BLOCK`"),
Token::KeywordEndFunctionBlock => write!(f, "`END_FUNCTION_BLOCK`"),
Token::KeywordType => write!(f, "`TYPE`"),
Token::KeywordStruct => write!(f, "`STRUCT`"),
Token::KeywordEndType => write!(f, "`END_TYPE`"),
Token::KeywordEndStruct => write!(f, "`END_STRUCT`"),
Token::KeywordActions => write!(f, "`ACTIONS`"),
Token::KeywordAction => write!(f, "`ACTION`"),
Token::KeywordEndAction => write!(f, "`END_ACTION`"),
Token::KeywordEndActions => write!(f, "`END_ACTIONS`"),
Token::KeywordColon => write!(f, "`:`"),
Token::KeywordSemicolon => write!(f, "`;`"),
Token::KeywordAssignment => write!(f, "`:=`"),
Token::KeywordOutputAssignment => write!(f, "`=>`"),
Token::KeywordReferenceAssignment => write!(f, "`REF=`"),
Token::KeywordParensOpen => write!(f, "`(`"),
Token::KeywordParensClose => write!(f, "`)`"),
Token::KeywordSquareParensOpen => write!(f, "`[`"),
Token::KeywordSquareParensClose => write!(f, "`]`"),
Token::KeywordComma => write!(f, "`,`"),
Token::KeywordDotDotDot => write!(f, "`...`"),
Token::KeywordDotDot => write!(f, "`..`"),
Token::KeywordDot => write!(f, "`.`"),
Token::KeywordIf => write!(f, "`IF`"),
Token::KeywordThen => write!(f, "`THEN`"),
Token::KeywordElseIf => write!(f, "`ELSIF`"),
Token::KeywordElse => write!(f, "`ELSE`"),
Token::KeywordEndIf => write!(f, "`END_IF`"),
Token::KeywordFor => write!(f, "`FOR`"),
Token::KeywordTo => write!(f, "`TO`"),
Token::KeywordBy => write!(f, "`BY`"),
Token::KeywordDo => write!(f, "`DO`"),
Token::KeywordEndFor => write!(f, "`END_FOR`"),
Token::KeywordWhile => write!(f, "`WHILE`"),
Token::KeywordEndWhile => write!(f, "`END_WHILE`"),
Token::KeywordRepeat => write!(f, "`REPEAT`"),
Token::KeywordUntil => write!(f, "`UNTIL`"),
Token::KeywordEndRepeat => write!(f, "`END_REPEAT`"),
Token::KeywordCase => write!(f, "`CASE`"),
Token::KeywordReturn => write!(f, "`RETURN`"),
Token::KeywordExit => write!(f, "`EXIT`"),
Token::KeywordContinue => write!(f, "`CONTINUE`"),
Token::KeywordPointer => write!(f, "`POINTER`"),
Token::KeywordFunctionPointer => write!(f, "`__FPOINTER`"),
Token::KeywordRef => write!(f, "`REF_TO`"),
Token::KeywordReferenceTo => write!(f, "`REFERENCE TO`"),
Token::KeywordArray => write!(f, "`ARRAY`"),
Token::KeywordString => write!(f, "`STRING`"),
Token::KeywordWideString => write!(f, "`WSTRING`"),
Token::KeywordOf => write!(f, "`OF`"),
Token::KeywordAt => write!(f, "`AT`"),
Token::KeywordEndCase => write!(f, "`END_CASE`"),
Token::OperatorPlus => write!(f, "`+`"),
Token::OperatorMinus => write!(f, "`-`"),
Token::OperatorMultiplication => write!(f, "`*`"),
Token::OperatorExponent => write!(f, "`**`"),
Token::OperatorDivision => write!(f, "`/`"),
Token::OperatorEqual => write!(f, "`=`"),
Token::OperatorNotEqual => write!(f, "`<>`"),
Token::OperatorLess => write!(f, "`<`"),
Token::OperatorGreater => write!(f, "`>`"),
Token::OperatorLessOrEqual => write!(f, "`<=`"),
Token::OperatorGreaterOrEqual => write!(f, "`>=`"),
Token::OperatorAmp => write!(f, "`&`"),
Token::OperatorDeref => write!(f, "`^`"),
Token::OperatorModulo => write!(f, "`MOD`"),
Token::OperatorAndThen => write!(f, "`AND_THEN`"),
Token::OperatorAnd => write!(f, "`AND`"),
Token::OperatorOrElse => write!(f, "`OR_ELSE`"),
Token::OperatorOr => write!(f, "`OR`"),
Token::OperatorXor => write!(f, "`XOR`"),
Token::OperatorNot => write!(f, "`NOT`"),
Token::Identifier => write!(f, "identifier"),
Token::LiteralIntegerHex
| Token::LiteralIntegerOct
| Token::LiteralIntegerBin
| Token::LiteralInteger => {
write!(f, "integer literal")
}
Token::LiteralNull => write!(f, "`NULL`"),
Token::LiteralTrue => write!(f, "`TRUE`"),
Token::LiteralFalse => write!(f, "`FALSE`"),
Token::LiteralDate => write!(f, "date literal"),
Token::LiteralDateAndTime => write!(f, "date and time literal"),
Token::LiteralTimeOfDay => write!(f, "time of day literal"),
Token::LiteralTime => write!(f, "time literal"),
Token::DirectAccess(_) => write!(f, "direct access"),
Token::HardwareAccess(_) => write!(f, "hardware access"),
Token::LiteralString => write!(f, "string literal"),
Token::LiteralWideString => write!(f, "wide string literal"),
Token::TypeCastPrefix => write!(f, "type cast prefix"),
Token::End => write!(f, "end of file"),
}
}
}
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