Merge pull request #4059 from ethereum/parser-simplify

Simplify the parser expectations

libsolidity/parsing/Parser.cpp

@@ -1194,7 +1194,8 @@ ASTPointer<Expression> Parser::parseExpression(
 	ASTPointer<Expression> expression = parseBinaryExpression(4, _lookAheadIndexAccessStructure);
 	if (Token::isAssignmentOp(m_scanner->currentToken()))
 	{
-		Token::Value assignmentOperator = expectAssignmentOperator();
+		Token::Value assignmentOperator = m_scanner->currentToken();
+		m_scanner->next();
 		ASTPointer<Expression> rightHandSide = parseExpression();
 		ASTNodeFactory nodeFactory(*this, expression);
 		nodeFactory.setEndPositionFromNode(rightHandSide);
@@ -1601,40 +1602,10 @@ ASTPointer<ParameterList> Parser::createEmptyParameterList()
 	return nodeFactory.createNode<ParameterList>(vector<ASTPointer<VariableDeclaration>>());
 }
 
-string Parser::currentTokenName()
-{
-	Token::Value token = m_scanner->currentToken();
-	if (Token::isElementaryTypeName(token)) //for the sake of accuracy in reporting
-	{
-		ElementaryTypeNameToken elemTypeName = m_scanner->currentElementaryTypeNameToken();
-		return elemTypeName.toString();
-	}
-	else
-		return Token::name(token);
-}
-
-Token::Value Parser::expectAssignmentOperator()
-{
-	Token::Value op = m_scanner->currentToken();
-	if (!Token::isAssignmentOp(op))
-		fatalParserError(
-			string("Expected assignment operator,  got '") +
-			currentTokenName() +
-			string("'")
-		);
-	m_scanner->next();
-	return op;
-}
-
 ASTPointer<ASTString> Parser::expectIdentifierToken()
 {
-	Token::Value id = m_scanner->currentToken();
-	if (id != Token::Identifier)
-		fatalParserError(
-			string("Expected identifier, got '") +
-			currentTokenName() +
-			string("'")
-		);
+	// do not advance on success
+	expectToken(Token::Identifier, false);
 	return getLiteralAndAdvance();
 }
 

libsolidity/parsing/Parser.h

@@ -165,8 +165,6 @@ private:
 	/// @returns an expression parsed in look-ahead fashion from something like "a.b[8][2**70]".
 	ASTPointer<Expression> expressionFromIndexAccessStructure(IndexAccessedPath const& _pathAndIndices);
 
-	std::string currentTokenName();
-	Token::Value expectAssignmentOperator();
 	ASTPointer<ASTString> expectIdentifierToken();
 	ASTPointer<ASTString> getLiteralAndAdvance();
 	///@}

libsolidity/parsing/ParserBase.cpp

@@ -63,7 +63,7 @@ Token::Value ParserBase::advance()
 	return m_scanner->next();
 }
 
-void ParserBase::expectToken(Token::Value _value)
+void ParserBase::expectToken(Token::Value _value, bool _advance)
 {
 	Token::Value tok = m_scanner->currentToken();
 	if (tok != _value)
@@ -98,7 +98,8 @@ void ParserBase::expectToken(Token::Value _value)
 				string("'")
 			);
 	}
-	m_scanner->next();
+	if (_advance)
+		m_scanner->next();
 }
 
 void ParserBase::increaseRecursionDepth()

libsolidity/parsing/ParserBase.h

@@ -63,7 +63,7 @@ protected:
 	///@{
 	///@name Helper functions
 	/// If current token value is not _value, throw exception otherwise advance token.
-	void expectToken(Token::Value _value);
+	void expectToken(Token::Value _value, bool _advance = true);
 	Token::Value currentToken() const;
 	Token::Value peekNextToken() const;
 	std::string currentLiteral() const;