Revert "Add Steve Johnson-style parser recovery rules:"

This reverts commit 97f8ee0d1b.

liblangutil/CharStream.cpp

@@ -73,13 +73,6 @@ char CharStream::rollback(size_t _amount)
 	return get();
 }
 
-char CharStream::setPosition(size_t _location)
-{
-	solAssert(_location <= m_source.size(), "Attempting to set position past end of source.");
-	m_position = _location;
-	return get();
-}
-
 string CharStream::lineAtPosition(int _position) const
 {
 	// if _position points to \n, it returns the line before the \n
@@ -113,3 +106,5 @@ tuple<int, int> CharStream::translatePositionToLineColumn(int _position) const
 	}
 	return tuple<int, int>(lineNumber, searchPosition - lineStart);
 }
+
+

liblangutil/CharStream.h

@@ -76,13 +76,7 @@ public:
 
 	char get(size_t _charsForward = 0) const { return m_source[m_position + _charsForward]; }
 	char advanceAndGet(size_t _chars = 1);
-	/// Sets scanner position to @ _amount characters backwards in source text.
-	/// @returns The character of the current location after update is returned.
 	char rollback(size_t _amount);
-	/// Sets scanner position to @ _location if it refers a valid offset in m_source.
-	/// If not, nothing is done.
-	/// @returns The character of the current location after update is returned.
-	char setPosition(size_t _location);
 
 	void reset() { m_position = 0; }
 

liblangutil/ErrorReporter.cpp

@@ -86,11 +86,6 @@ void ErrorReporter::error(Error::Type _type, SourceLocation const& _location, Se
 	m_errorList.push_back(err);
 }
 
-bool ErrorReporter::hasExcessiveErrors() const
-{
-	return m_errorCount > c_maxErrorsAllowed;
-}
-
 bool ErrorReporter::checkForExcessiveErrors(Error::Type _type)
 {
 	if (_type == Error::Type::Warning)

liblangutil/ErrorReporter.h

@@ -118,9 +118,6 @@ public:
 		return m_errorCount > 0;
 	}
 
-	// @returns true if the maximum error count has been reached.
-	bool hasExcessiveErrors() const;
-
 private:
 	void error(
 		Error::Type _type,
@@ -152,3 +149,4 @@ private:
 };
 
 }
+

liblangutil/ParserBase.cpp

@@ -47,7 +47,7 @@ Token ParserBase::peekNextToken() const
 	return m_scanner->peekNextToken();
 }
 
-string ParserBase::currentLiteral() const
+std::string ParserBase::currentLiteral() const
 {
 	return m_scanner->currentLiteral();
 }
@@ -57,79 +57,30 @@ Token ParserBase::advance()
 	return m_scanner->next();
 }
 
-string ParserBase::tokenName(Token _token)
-{
-	if (_token == Token::Identifier)
-		return "identifier";
-	else if (_token == Token::EOS)
-		return "end of source";
-	else if (TokenTraits::isReservedKeyword(_token))
-		return "reserved keyword '" + TokenTraits::friendlyName(_token) + "'";
-	else if (TokenTraits::isElementaryTypeName(_token)) //for the sake of accuracy in reporting
-	{
-		ElementaryTypeNameToken elemTypeName = m_scanner->currentElementaryTypeNameToken();
-		return "'" + elemTypeName.toString() + "'";
-	}
-	else
-		return "'" + TokenTraits::friendlyName(_token) + "'";
-}
-
 void ParserBase::expectToken(Token _value, bool _advance)
 {
 	Token tok = m_scanner->currentToken();
 	if (tok != _value)
 	{
-		string const expectedToken = ParserBase::tokenName(_value);
-		if (m_parserErrorRecovery)
-			parserError("Expected " + expectedToken + " but got " + tokenName(tok));
-		else
-			fatalParserError("Expected " + expectedToken + " but got " + tokenName(tok));
-		// Do not advance so that recovery can sync or make use of the current token.
-		// This is especially useful if the expected token
-		// is the only one that is missing and is at the end of a construct.
-		// "{ ... ; }" is such an example.
-		//        ^
-		_advance = false;
-	}
-	if (_advance)
-		m_scanner->next();
-}
-
-void ParserBase::expectTokenOrConsumeUntil(Token _value, string const& _currentNodeName, bool _advance)
-{
-	Token tok = m_scanner->currentToken();
-	if (tok != _value)
-	{
-		int startPosition = position();
-		SourceLocation errorLoc = SourceLocation{startPosition, endPosition(), source()};
-		while (m_scanner->currentToken() != _value && m_scanner->currentToken() != Token::EOS)
-			m_scanner->next();
-
-		string const expectedToken = ParserBase::tokenName(_value);
-		string const msg = "In " + _currentNodeName + ", " + expectedToken + "is expected; got " +  ParserBase::tokenName(tok) +  "instead.";
-		if (m_scanner->currentToken() == Token::EOS)
+		auto tokenName = [this](Token _token)
 		{
-			// rollback to where the token started, and raise exception to be caught at a higher level.
-			m_scanner->setPosition(startPosition);
-			m_inParserRecovery = true;
-			fatalParserError(errorLoc, msg);
-		}
-		else
-		{
-			if (m_inParserRecovery)
-				parserWarning("Recovered in " + _currentNodeName + " at " + expectedToken + ".");
+			if (_token == Token::Identifier)
+				return string("identifier");
+			else if (_token == Token::EOS)
+				return string("end of source");
+			else if (TokenTraits::isReservedKeyword(_token))
+				return string("reserved keyword '") + TokenTraits::friendlyName(_token) + "'";
+			else if (TokenTraits::isElementaryTypeName(_token)) //for the sake of accuracy in reporting
+			{
+				ElementaryTypeNameToken elemTypeName = m_scanner->currentElementaryTypeNameToken();
+				return string("'") + elemTypeName.toString() + "'";
+			}
 			else
-				parserError(errorLoc, msg + "Recovered at next " + expectedToken);
-			m_inParserRecovery = false;
-		}
-	}
-	else if (m_inParserRecovery)
-	{
-		string expectedToken = ParserBase::tokenName(_value);
-		parserWarning("Recovered in " + _currentNodeName + " at " + expectedToken + ".");
-		m_inParserRecovery = false;
-	}
+				return string("'") + TokenTraits::friendlyName(_token) + "'";
+		};
 
+		fatalParserError(string("Expected ") + tokenName(_value) + string(" but got ") + tokenName(tok));
+	}
 	if (_advance)
 		m_scanner->next();
 }
@@ -147,27 +98,12 @@ void ParserBase::decreaseRecursionDepth()
 	m_recursionDepth--;
 }
 
-void ParserBase::parserWarning(string const& _description)
-{
-	m_errorReporter.warning(SourceLocation{position(), endPosition(), source()}, _description);
-}
-
-void ParserBase::parserError(SourceLocation const& _location, string const& _description)
-{
-	m_errorReporter.parserError(_location, _description);
-}
-
 void ParserBase::parserError(string const& _description)
 {
-	parserError(SourceLocation{position(), endPosition(), source()}, _description);
+	m_errorReporter.parserError(SourceLocation{position(), endPosition(), source()}, _description);
 }
 
 void ParserBase::fatalParserError(string const& _description)
 {
-	fatalParserError(SourceLocation{position(), endPosition(), source()}, _description);
-}
-
-void ParserBase::fatalParserError(SourceLocation const& _location, string const& _description)
-{
-	m_errorReporter.fatalParserError(_location, _description);
+	m_errorReporter.fatalParserError(SourceLocation{position(), endPosition(), source()}, _description);
 }

liblangutil/ParserBase.h

@@ -36,14 +36,7 @@ class Scanner;
 class ParserBase
 {
 public:
-	/// Set @a _parserErrorRecovery to true for additional error
-	/// recovery.  This is experimental and intended for use
-	/// by front-end tools that need partial AST information even
-	/// when errors occur.
-	explicit ParserBase(ErrorReporter& errorReporter, bool _parserErrorRecovery = false): m_errorReporter(errorReporter)
-	{
-		m_parserErrorRecovery = _parserErrorRecovery;
-	}
+	explicit ParserBase(ErrorReporter& errorReporter): m_errorReporter(errorReporter) {}
 
 	std::shared_ptr<CharStream> source() const { return m_scanner->charStream(); }
 
@@ -69,17 +62,10 @@ protected:
 
 	///@{
 	///@name Helper functions
-	/// If current token value is not @a _value, throw exception otherwise advance token
-	//  @a if _advance is true and error recovery is in effect.
+	/// If current token value is not _value, throw exception otherwise advance token.
 	void expectToken(Token _value, bool _advance = true);
-
-	/// Like expectToken but if there is an error ignores tokens until
-	/// the expected token or EOS is seen. If EOS is encountered, back up to the error point,
-	/// and throw an exception so that a higher grammar rule has an opportunity to recover.
-	void expectTokenOrConsumeUntil(Token _value, std::string const& _currentNodeName, bool _advance = true);
 	Token currentToken() const;
 	Token peekNextToken() const;
-	std::string tokenName(Token _token);
 	std::string currentLiteral() const;
 	Token advance();
 	///@}
@@ -91,26 +77,16 @@ protected:
 	/// Creates a @ref ParserError and annotates it with the current position and the
 	/// given @a _description.
 	void parserError(std::string const& _description);
-	void parserError(SourceLocation const& _location, std::string const& _description);
-
-	/// Creates a @ref ParserWarning and annotates it with the current position and the
-	/// given @a _description.
-	void parserWarning(std::string const& _description);
 
 	/// Creates a @ref ParserError and annotates it with the current position and the
 	/// given @a _description. Throws the FatalError.
 	void fatalParserError(std::string const& _description);
-	void fatalParserError(SourceLocation const& _location, std::string const& _description);
 
 	std::shared_ptr<Scanner> m_scanner;
 	/// The reference to the list of errors and warning to add errors/warnings during parsing
 	ErrorReporter& m_errorReporter;
 	/// Current recursion depth during parsing.
 	size_t m_recursionDepth = 0;
-	/// True if we are in parser error recovery. Usually this means we are scanning for
-	/// a synchronization token like ';', or '}'. We use this to reduce cascaded error messages.
-	bool m_inParserRecovery = false;
-	bool m_parserErrorRecovery = false;
 };
 
 }

liblangutil/Scanner.cpp

@@ -156,13 +156,6 @@ void Scanner::reset()
 	next();
 }
 
-void Scanner::setPosition(size_t _offset)
-{
-	m_char = m_source->setPosition(_offset);
-	scanToken();
-	next();
-}
-
 void Scanner::supportPeriodInIdentifier(bool _value)
 {
 	m_supportPeriodInIdentifier = _value;

liblangutil/Scanner.h

@@ -110,9 +110,6 @@ public:
 	/// @returns the next token and advances input
 	Token next();
 
-	/// Set scanner to a specific offset. This is used in error recovery.
-	void setPosition(size_t _offset);
-
 	///@{
 	///@name Information about the current token