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/*
This file is part of cpp-ethereum.
cpp-ethereum is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
cpp-ethereum is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @author Christian <c@ethdev.com>
* @date 2014
* Solidity parser.
*/
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#include <vector>
#include <libdevcore/Log.h>
#include <libsolidity/BaseTypes.h>
#include <libsolidity/Parser.h>
#include <libsolidity/Scanner.h>
#include <libsolidity/Exceptions.h>
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using namespace std;
namespace dev
{
namespace solidity
{
/// AST node factory that also tracks the begin and end position of an AST node
/// while it is being parsed
class Parser::ASTNodeFactory
{
public:
ASTNodeFactory(Parser const& _parser):
m_parser(_parser), m_location(_parser.getPosition(), -1, _parser.getSourceName()) {}
void markEndPosition() { m_location.end = m_parser.getEndPosition(); }
void setLocationEmpty() { m_location.end = m_location.start; }
/// Set the end position to the one of the given node.
void setEndPositionFromNode(ASTPointer<ASTNode> const& _node) { m_location.end = _node->getLocation().end; }
template <class NodeType, typename... Args>
ASTPointer<NodeType> createNode(Args&& ... _args)
{
if (m_location.end < 0)
markEndPosition();
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return make_shared<NodeType>(m_location, forward<Args>(_args)...);
}
private:
Parser const& m_parser;
Location m_location;
};
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ASTPointer<SourceUnit> Parser::parse(shared_ptr<Scanner> const& _scanner)
{
m_scanner = _scanner;
ASTNodeFactory nodeFactory(*this);
vector<ASTPointer<ASTNode>> nodes;
while (_scanner->getCurrentToken() != Token::EOS)
{
switch (m_scanner->getCurrentToken())
{
case Token::IMPORT:
nodes.push_back(parseImportDirective());
break;
case Token::CONTRACT:
nodes.push_back(parseContractDefinition());
break;
default:
BOOST_THROW_EXCEPTION(createParserError(std::string("Expected import directive or contract definition.")));
}
}
return nodeFactory.createNode<SourceUnit>(nodes);
}
std::shared_ptr<const string> const& Parser::getSourceName() const
{
return m_scanner->getSourceName();
}
int Parser::getPosition() const
{
return m_scanner->getCurrentLocation().start;
}
int Parser::getEndPosition() const
{
return m_scanner->getCurrentLocation().end;
}
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ASTPointer<ImportDirective> Parser::parseImportDirective()
{
ASTNodeFactory nodeFactory(*this);
expectToken(Token::IMPORT);
if (m_scanner->getCurrentToken() != Token::STRING_LITERAL)
BOOST_THROW_EXCEPTION(createParserError("Expected string literal (URL)."));
ASTPointer<ASTString> url = getLiteralAndAdvance();
nodeFactory.markEndPosition();
expectToken(Token::SEMICOLON);
return nodeFactory.createNode<ImportDirective>(url);
}
ASTPointer<ContractDefinition> Parser::parseContractDefinition()
{
ASTNodeFactory nodeFactory(*this);
ASTPointer<ASTString> docstring;
if (m_scanner->getCurrentCommentLiteral() != "")
docstring = make_shared<ASTString>(m_scanner->getCurrentCommentLiteral());
expectToken(Token::CONTRACT);
ASTPointer<ASTString> name = expectIdentifierToken();
expectToken(Token::LBRACE);
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vector<ASTPointer<StructDefinition>> structs;
vector<ASTPointer<VariableDeclaration>> stateVariables;
vector<ASTPointer<FunctionDefinition>> functions;
bool visibilityIsPublic = true;
while (true)
{
Token::Value currentToken = m_scanner->getCurrentToken();
if (currentToken == Token::RBRACE)
break;
else if (currentToken == Token::PUBLIC || currentToken == Token::PRIVATE)
{
visibilityIsPublic = (m_scanner->getCurrentToken() == Token::PUBLIC);
m_scanner->next();
expectToken(Token::COLON);
}
else if (currentToken == Token::FUNCTION)
functions.push_back(parseFunctionDefinition(visibilityIsPublic));
else if (currentToken == Token::STRUCT)
structs.push_back(parseStructDefinition());
else if (currentToken == Token::IDENTIFIER || currentToken == Token::MAPPING ||
Token::isElementaryTypeName(currentToken))
{
bool const allowVar = false;
stateVariables.push_back(parseVariableDeclaration(allowVar));
expectToken(Token::SEMICOLON);
}
else
BOOST_THROW_EXCEPTION(createParserError("Function, variable or struct declaration expected."));
}
nodeFactory.markEndPosition();
expectToken(Token::RBRACE);
return nodeFactory.createNode<ContractDefinition>(name, docstring, structs, stateVariables, functions);
}
ASTPointer<FunctionDefinition> Parser::parseFunctionDefinition(bool _isPublic)
{
ASTNodeFactory nodeFactory(*this);
ASTPointer<ASTString> docstring;
if (m_scanner->getCurrentCommentLiteral() != "")
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docstring = make_shared<ASTString>(m_scanner->getCurrentCommentLiteral());
expectToken(Token::FUNCTION);
ASTPointer<ASTString> name(expectIdentifierToken());
ASTPointer<ParameterList> parameters(parseParameterList());
bool isDeclaredConst = false;
if (m_scanner->getCurrentToken() == Token::CONST)
{
isDeclaredConst = true;
m_scanner->next();
}
ASTPointer<ParameterList> returnParameters;
if (m_scanner->getCurrentToken() == Token::RETURNS)
{
bool const permitEmptyParameterList = false;
m_scanner->next();
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returnParameters = parseParameterList(permitEmptyParameterList);
}
else
{
// create an empty parameter list at a zero-length location
ASTNodeFactory nodeFactory(*this);
nodeFactory.setLocationEmpty();
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returnParameters = nodeFactory.createNode<ParameterList>(vector<ASTPointer<VariableDeclaration>>());
}
ASTPointer<Block> block = parseBlock();
nodeFactory.setEndPositionFromNode(block);
return nodeFactory.createNode<FunctionDefinition>(name, _isPublic, docstring,
parameters,
isDeclaredConst, returnParameters, block);
}
ASTPointer<StructDefinition> Parser::parseStructDefinition()
{
ASTNodeFactory nodeFactory(*this);
expectToken(Token::STRUCT);
ASTPointer<ASTString> name = expectIdentifierToken();
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vector<ASTPointer<VariableDeclaration>> members;
expectToken(Token::LBRACE);
while (m_scanner->getCurrentToken() != Token::RBRACE)
{
bool const allowVar = false;
members.push_back(parseVariableDeclaration(allowVar));
expectToken(Token::SEMICOLON);
}
nodeFactory.markEndPosition();
expectToken(Token::RBRACE);
return nodeFactory.createNode<StructDefinition>(name, members);
}
ASTPointer<VariableDeclaration> Parser::parseVariableDeclaration(bool _allowVar)
{
ASTNodeFactory nodeFactory(*this);
ASTPointer<TypeName> type = parseTypeName(_allowVar);
nodeFactory.markEndPosition();
return nodeFactory.createNode<VariableDeclaration>(type, expectIdentifierToken());
}
ASTPointer<TypeName> Parser::parseTypeName(bool _allowVar)
{
ASTPointer<TypeName> type;
Token::Value token = m_scanner->getCurrentToken();
if (Token::isElementaryTypeName(token))
{
type = ASTNodeFactory(*this).createNode<ElementaryTypeName>(token);
m_scanner->next();
}
else if (token == Token::VAR)
{
if (!_allowVar)
BOOST_THROW_EXCEPTION(createParserError("Expected explicit type name."));
m_scanner->next();
}
else if (token == Token::MAPPING)
{
type = parseMapping();
}
else if (token == Token::IDENTIFIER)
{
ASTNodeFactory nodeFactory(*this);
nodeFactory.markEndPosition();
type = nodeFactory.createNode<UserDefinedTypeName>(expectIdentifierToken());
}
else
BOOST_THROW_EXCEPTION(createParserError("Expected type name"));
return type;
}
ASTPointer<Mapping> Parser::parseMapping()
{
ASTNodeFactory nodeFactory(*this);
expectToken(Token::MAPPING);
expectToken(Token::LPAREN);
if (!Token::isElementaryTypeName(m_scanner->getCurrentToken()))
BOOST_THROW_EXCEPTION(createParserError("Expected elementary type name for mapping key type"));
ASTPointer<ElementaryTypeName> keyType;
keyType = ASTNodeFactory(*this).createNode<ElementaryTypeName>(m_scanner->getCurrentToken());
m_scanner->next();
expectToken(Token::ARROW);
bool const allowVar = false;
ASTPointer<TypeName> valueType = parseTypeName(allowVar);
nodeFactory.markEndPosition();
expectToken(Token::RPAREN);
return nodeFactory.createNode<Mapping>(keyType, valueType);
}
ASTPointer<ParameterList> Parser::parseParameterList(bool _allowEmpty)
{
ASTNodeFactory nodeFactory(*this);
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vector<ASTPointer<VariableDeclaration>> parameters;
expectToken(Token::LPAREN);
if (!_allowEmpty || m_scanner->getCurrentToken() != Token::RPAREN)
{
bool const allowVar = false;
parameters.push_back(parseVariableDeclaration(allowVar));
while (m_scanner->getCurrentToken() != Token::RPAREN)
{
expectToken(Token::COMMA);
parameters.push_back(parseVariableDeclaration(allowVar));
}
}
nodeFactory.markEndPosition();
m_scanner->next();
return nodeFactory.createNode<ParameterList>(parameters);
}
ASTPointer<Block> Parser::parseBlock()
{
ASTNodeFactory nodeFactory(*this);
expectToken(Token::LBRACE);
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vector<ASTPointer<Statement>> statements;
while (m_scanner->getCurrentToken() != Token::RBRACE)
statements.push_back(parseStatement());
nodeFactory.markEndPosition();
expectToken(Token::RBRACE);
return nodeFactory.createNode<Block>(statements);
}
ASTPointer<Statement> Parser::parseStatement()
{
ASTPointer<Statement> statement;
switch (m_scanner->getCurrentToken())
{
case Token::IF:
return parseIfStatement();
case Token::WHILE:
return parseWhileStatement();
case Token::LBRACE:
return parseBlock();
// starting from here, all statements must be terminated by a semicolon
case Token::CONTINUE:
statement = ASTNodeFactory(*this).createNode<Continue>();
m_scanner->next();
break;
case Token::BREAK:
statement = ASTNodeFactory(*this).createNode<Break>();
m_scanner->next();
break;
case Token::RETURN:
{
ASTNodeFactory nodeFactory(*this);
ASTPointer<Expression> expression;
if (m_scanner->next() != Token::SEMICOLON)
{
expression = parseExpression();
nodeFactory.setEndPositionFromNode(expression);
}
statement = nodeFactory.createNode<Return>(expression);
}
break;
default:
// distinguish between variable definition (and potentially assignment) and expression statement
// (which include assignments to other expressions and pre-declared variables)
// We have a variable definition if we get a keyword that specifies a type name, or
// in the case of a user-defined type, we have two identifiers following each other.
if (m_scanner->getCurrentToken() == Token::MAPPING ||
m_scanner->getCurrentToken() == Token::VAR ||
((Token::isElementaryTypeName(m_scanner->getCurrentToken()) ||
m_scanner->getCurrentToken() == Token::IDENTIFIER) &&
m_scanner->peekNextToken() == Token::IDENTIFIER))
statement = parseVariableDefinition();
else // "ordinary" expression statement
statement = parseExpressionStatement();
}
expectToken(Token::SEMICOLON);
return statement;
}
ASTPointer<IfStatement> Parser::parseIfStatement()
{
ASTNodeFactory nodeFactory(*this);
expectToken(Token::IF);
expectToken(Token::LPAREN);
ASTPointer<Expression> condition = parseExpression();
expectToken(Token::RPAREN);
ASTPointer<Statement> trueBody = parseStatement();
ASTPointer<Statement> falseBody;
if (m_scanner->getCurrentToken() == Token::ELSE)
{
m_scanner->next();
falseBody = parseStatement();
nodeFactory.setEndPositionFromNode(falseBody);
}
else
nodeFactory.setEndPositionFromNode(trueBody);
return nodeFactory.createNode<IfStatement>(condition, trueBody, falseBody);
}
ASTPointer<WhileStatement> Parser::parseWhileStatement()
{
ASTNodeFactory nodeFactory(*this);
expectToken(Token::WHILE);
expectToken(Token::LPAREN);
ASTPointer<Expression> condition = parseExpression();
expectToken(Token::RPAREN);
ASTPointer<Statement> body = parseStatement();
nodeFactory.setEndPositionFromNode(body);
return nodeFactory.createNode<WhileStatement>(condition, body);
}
ASTPointer<VariableDefinition> Parser::parseVariableDefinition()
{
ASTNodeFactory nodeFactory(*this);
bool const allowVar = true;
ASTPointer<VariableDeclaration> variable = parseVariableDeclaration(allowVar);
ASTPointer<Expression> value;
if (m_scanner->getCurrentToken() == Token::ASSIGN)
{
m_scanner->next();
value = parseExpression();
nodeFactory.setEndPositionFromNode(value);
}
else
nodeFactory.setEndPositionFromNode(variable);
return nodeFactory.createNode<VariableDefinition>(variable, value);
}
ASTPointer<ExpressionStatement> Parser::parseExpressionStatement()
{
ASTNodeFactory nodeFactory(*this);
ASTPointer<Expression> expression = parseExpression();
nodeFactory.setEndPositionFromNode(expression);
return nodeFactory.createNode<ExpressionStatement>(expression);
}
ASTPointer<Expression> Parser::parseExpression()
{
ASTNodeFactory nodeFactory(*this);
ASTPointer<Expression> expression = parseBinaryExpression();
if (!Token::isAssignmentOp(m_scanner->getCurrentToken()))
return expression;
Token::Value assignmentOperator = expectAssignmentOperator();
ASTPointer<Expression> rightHandSide = parseExpression();
nodeFactory.setEndPositionFromNode(rightHandSide);
return nodeFactory.createNode<Assignment>(expression, assignmentOperator, rightHandSide);
}
ASTPointer<Expression> Parser::parseBinaryExpression(int _minPrecedence)
{
ASTNodeFactory nodeFactory(*this);
ASTPointer<Expression> expression = parseUnaryExpression();
int precedence = Token::precedence(m_scanner->getCurrentToken());
for (; precedence >= _minPrecedence; --precedence)
{
while (Token::precedence(m_scanner->getCurrentToken()) == precedence)
{
Token::Value op = m_scanner->getCurrentToken();
m_scanner->next();
ASTPointer<Expression> right = parseBinaryExpression(precedence + 1);
nodeFactory.setEndPositionFromNode(right);
expression = nodeFactory.createNode<BinaryOperation>(expression, op, right);
}
}
return expression;
}
ASTPointer<Expression> Parser::parseUnaryExpression()
{
ASTNodeFactory nodeFactory(*this);
Token::Value token = m_scanner->getCurrentToken();
if (Token::isUnaryOp(token) || Token::isCountOp(token))
{
// prefix expression
m_scanner->next();
ASTPointer<Expression> subExpression = parseUnaryExpression();
nodeFactory.setEndPositionFromNode(subExpression);
return nodeFactory.createNode<UnaryOperation>(token, subExpression, true);
}
else
{
// potential postfix expression
ASTPointer<Expression> subExpression = parseLeftHandSideExpression();
token = m_scanner->getCurrentToken();
if (!Token::isCountOp(token))
return subExpression;
nodeFactory.markEndPosition();
m_scanner->next();
return nodeFactory.createNode<UnaryOperation>(token, subExpression, false);
}
}
ASTPointer<Expression> Parser::parseLeftHandSideExpression()
{
ASTNodeFactory nodeFactory(*this);
ASTPointer<Expression> expression = parsePrimaryExpression();
while (true)
{
switch (m_scanner->getCurrentToken())
{
case Token::LBRACK:
{
m_scanner->next();
ASTPointer<Expression> index = parseExpression();
nodeFactory.markEndPosition();
expectToken(Token::RBRACK);
expression = nodeFactory.createNode<IndexAccess>(expression, index);
}
break;
case Token::PERIOD:
{
m_scanner->next();
nodeFactory.markEndPosition();
expression = nodeFactory.createNode<MemberAccess>(expression, expectIdentifierToken());
}
break;
case Token::LPAREN:
{
m_scanner->next();
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vector<ASTPointer<Expression>> arguments = parseFunctionCallArguments();
nodeFactory.markEndPosition();
expectToken(Token::RPAREN);
expression = nodeFactory.createNode<FunctionCall>(expression, arguments);
}
break;
default:
return expression;
}
}
}
ASTPointer<Expression> Parser::parsePrimaryExpression()
{
ASTNodeFactory nodeFactory(*this);
Token::Value token = m_scanner->getCurrentToken();
ASTPointer<Expression> expression;
switch (token)
{
case Token::TRUE_LITERAL:
case Token::FALSE_LITERAL:
expression = nodeFactory.createNode<Literal>(token, getLiteralAndAdvance());
break;
case Token::NUMBER:
case Token::STRING_LITERAL:
nodeFactory.markEndPosition();
expression = nodeFactory.createNode<Literal>(token, getLiteralAndAdvance());
break;
case Token::IDENTIFIER:
nodeFactory.markEndPosition();
expression = nodeFactory.createNode<Identifier>(getLiteralAndAdvance());
break;
case Token::LPAREN:
{
m_scanner->next();
ASTPointer<Expression> expression = parseExpression();
expectToken(Token::RPAREN);
return expression;
}
default:
if (Token::isElementaryTypeName(token))
{
// used for casts
expression = nodeFactory.createNode<ElementaryTypeNameExpression>(token);
m_scanner->next();
}
else
{
BOOST_THROW_EXCEPTION(createParserError("Expected primary expression."));
return ASTPointer<Expression>(); // this is not reached
}
break;
}
return expression;
}
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vector<ASTPointer<Expression>> Parser::parseFunctionCallArguments()
{
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vector<ASTPointer<Expression>> arguments;
if (m_scanner->getCurrentToken() != Token::RPAREN)
{
arguments.push_back(parseExpression());
while (m_scanner->getCurrentToken() != Token::RPAREN)
{
expectToken(Token::COMMA);
arguments.push_back(parseExpression());
}
}
return arguments;
}
void Parser::expectToken(Token::Value _value)
{
if (m_scanner->getCurrentToken() != _value)
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BOOST_THROW_EXCEPTION(createParserError(string("Expected token ") + string(Token::getName(_value))));
m_scanner->next();
}
Token::Value Parser::expectAssignmentOperator()
{
Token::Value op = m_scanner->getCurrentToken();
if (!Token::isAssignmentOp(op))
BOOST_THROW_EXCEPTION(createParserError("Expected assignment operator"));
m_scanner->next();
return op;
}
ASTPointer<ASTString> Parser::expectIdentifierToken()
{
if (m_scanner->getCurrentToken() != Token::IDENTIFIER)
BOOST_THROW_EXCEPTION(createParserError("Expected identifier"));
return getLiteralAndAdvance();
}
ASTPointer<ASTString> Parser::getLiteralAndAdvance()
{
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ASTPointer<ASTString> identifier = make_shared<ASTString>(m_scanner->getCurrentLiteral());
m_scanner->next();
return identifier;
}
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ParserError Parser::createParserError(string const& _description) const
{
return ParserError() << errinfo_sourceLocation(Location(getPosition(), getPosition(), getSourceName()))
<< errinfo_comment(_description);
}
}
}