path: root/AST.h

/*
    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 abstract syntax tree.
 */

#pragma once


#include <string>
#include <vector>
#include <memory>
#include <boost/noncopyable.hpp>
#include <libsolidity/ASTForward.h>
#include <libsolidity/BaseTypes.h>
#include <libsolidity/Token.h>
#include <libsolidity/Types.h>
#include <libsolidity/Exceptions.h>

namespace dev
{
namespace solidity
{

class ASTVisitor;


/// The root (abstract) class of the AST inheritance tree.
/// It is possible to traverse all direct and indirect children of an AST node by calling
/// accept, providing an ASTVisitor.
class ASTNode: private boost::noncopyable
{
public:
    explicit ASTNode(Location const& _location): m_location(_location) {}

    virtual ~ASTNode() {}

    virtual void accept(ASTVisitor& _visitor) = 0;
    template <class T>
    static void listAccept(std::vector<ASTPointer<T>>& _list, ASTVisitor& _visitor)
    {
        for (ASTPointer<T>& element: _list)
            element->accept(_visitor);
    }

    /// Returns the source code location of this node.
    Location const& getLocation() const { return m_location; }

    /// Creates a @ref TypeError exception and decorates it with the location of the node and
    /// the given description
    TypeError createTypeError(std::string const& _description);

    ///@{
    ///@name equality operators
    /// Equality relies on the fact that nodes cannot be copied.
    bool operator==(ASTNode const& _other) const { return this == &_other; }
    bool operator!=(ASTNode const& _other) const { return !operator==(_other); }
    ///@}

private:
    Location m_location;
};

/// Abstract AST class for a declaration (contract, function, struct, variable).
class Declaration: public ASTNode
{
public:
    Declaration(Location const& _location, ASTPointer<ASTString> const& _name):
        ASTNode(_location), m_name(_name) {}

    /// Returns the declared name.
    const ASTString& getName() const { return *m_name; }

private:
    ASTPointer<ASTString> m_name;
};

/// Definition of a contract. This is the only AST nodes where child nodes are not visited in
/// document order. It first visits all struct declarations, then all variable declarations and
/// finally all function declarations.
class ContractDefinition: public Declaration
{
public:
    ContractDefinition(Location const& _location,
                       ASTPointer<ASTString> const& _name,
                       std::vector<ASTPointer<StructDefinition>> const& _definedStructs,
                       std::vector<ASTPointer<VariableDeclaration>> const& _stateVariables,
                       std::vector<ASTPointer<FunctionDefinition>> const& _definedFunctions):
        Declaration(_location, _name),
        m_definedStructs(_definedStructs),
        m_stateVariables(_stateVariables),
        m_definedFunctions(_definedFunctions)
    {}

    virtual void accept(ASTVisitor& _visitor) override;

    std::vector<ASTPointer<StructDefinition>> const& getDefinedStructs() { return m_definedStructs; }
    std::vector<ASTPointer<VariableDeclaration>> const& getStateVariables() { return m_stateVariables; }
    std::vector<ASTPointer<FunctionDefinition>> const& getDefinedFunctions() { return m_definedFunctions; }

private:
    std::vector<ASTPointer<StructDefinition>> m_definedStructs;
    std::vector<ASTPointer<VariableDeclaration>> m_stateVariables;
    std::vector<ASTPointer<FunctionDefinition>> m_definedFunctions;
};

class StructDefinition: public Declaration
{
public:
    StructDefinition(Location const& _location,
                     ASTPointer<ASTString> const& _name,
                     std::vector<ASTPointer<VariableDeclaration>> const& _members):
        Declaration(_location, _name), m_members(_members) {}
    virtual void accept(ASTVisitor& _visitor) override;

private:
    std::vector<ASTPointer<VariableDeclaration>> m_members;
};

/// Parameter list, used as function parameter list and return list.
/// None of the parameters is allowed to contain mappings (not even recursively
/// inside structs), but (@todo) this is not yet enforced.
class ParameterList: public ASTNode
{
public:
    ParameterList(Location const& _location,
                  std::vector<ASTPointer<VariableDeclaration>> const& _parameters):
        ASTNode(_location), m_parameters(_parameters) {}
    virtual void accept(ASTVisitor& _visitor) override;

    std::vector<ASTPointer<VariableDeclaration>> const& getParameters() { return m_parameters; }

private:
    std::vector<ASTPointer<VariableDeclaration>> m_parameters;
};

class FunctionDefinition: public Declaration
{
public:
    FunctionDefinition(Location const& _location, ASTPointer<ASTString> const& _name, bool _isPublic,
                       ASTPointer<ParameterList> const& _parameters,
                       bool _isDeclaredConst,
                       ASTPointer<ParameterList> const& _returnParameters,
                       ASTPointer<Block> const& _body):
        Declaration(_location, _name), m_isPublic(_isPublic), m_parameters(_parameters),
        m_isDeclaredConst(_isDeclaredConst), m_returnParameters(_returnParameters),
        m_body(_body) {}
    virtual void accept(ASTVisitor& _visitor) override;

    bool isPublic() const { return m_isPublic; }
    bool isDeclaredConst() const { return m_isDeclaredConst; }
    std::vector<ASTPointer<VariableDeclaration>> const& getParameters() const { return m_parameters->getParameters(); }
    ParameterList& getParameterList() { return *m_parameters; }
    ASTPointer<ParameterList> const& getReturnParameterList() const { return m_returnParameters; }
    Block& getBody() { return *m_body; }

private:
    bool m_isPublic;
    ASTPointer<ParameterList> m_parameters;
    bool m_isDeclaredConst;
    ASTPointer<ParameterList> m_returnParameters;
    ASTPointer<Block> m_body;
};

/// Declaration of a variable. This can be used in various places, e.g. in function parameter
/// lists, struct definitions and even function bodys.
class VariableDeclaration: public Declaration
{
public:
    VariableDeclaration(Location const& _location, ASTPointer<TypeName> const& _type,
                        ASTPointer<ASTString> const& _name):
        Declaration(_location, _name), m_typeName(_type) {}
    virtual void accept(ASTVisitor& _visitor) override;

    bool isTypeGivenExplicitly() const { return bool(m_typeName); }
    TypeName* getTypeName() const { return m_typeName.get(); }

    //! Returns the declared or inferred type. Can be an empty pointer if no type was explicitly
    //! declared and there is no assignment to the variable that fixes the type.
    std::shared_ptr<Type const> const& getType() const { return m_type; }
    void setType(std::shared_ptr<Type const> const& _type) { m_type = _type; }

private:
    ASTPointer<TypeName> m_typeName; ///< can be empty ("var")

    std::shared_ptr<Type const> m_type; ///< derived type, initially empty
};

/// Types
/// @{

/// Abstract base class of a type name, can be any built-in or user-defined type.
class TypeName: public ASTNode
{
public:
    explicit TypeName(Location const& _location): ASTNode(_location) {}
    virtual void accept(ASTVisitor& _visitor) override;

    /// Retrieve the element of the type hierarchy this node refers to. Can return an empty shared
    /// pointer until the types have been resolved using the @ref NameAndTypeResolver.
    virtual std::shared_ptr<Type> toType() = 0;
};

/// Any pre-defined type name represented by a single keyword, i.e. it excludes mappings,
/// contracts, functions, etc.
class ElementaryTypeName: public TypeName
{
public:
    explicit ElementaryTypeName(Location const& _location, Token::Value _type):
        TypeName(_location), m_type(_type) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual std::shared_ptr<Type> toType() override { return Type::fromElementaryTypeName(m_type); }

    Token::Value getTypeName() const { return m_type; }

private:
    Token::Value m_type;
};

/// Name referring to a user-defined type (i.e. a struct).
/// @todo some changes are necessary if this is also used to refer to contract types later
class UserDefinedTypeName: public TypeName
{
public:
    UserDefinedTypeName(Location const& _location, ASTPointer<ASTString> const& _name):
        TypeName(_location), m_name(_name) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual std::shared_ptr<Type> toType() override { return Type::fromUserDefinedTypeName(*this); }

    const ASTString& getName() const { return *m_name; }
    void setReferencedStruct(StructDefinition& _referencedStruct) { m_referencedStruct = &_referencedStruct; }
    StructDefinition const* getReferencedStruct() const { return m_referencedStruct; }

private:
    ASTPointer<ASTString> m_name;

    StructDefinition* m_referencedStruct;
};

/// A mapping type. Its source form is "mapping('keyType' => 'valueType')"
class Mapping: public TypeName
{
public:
    Mapping(Location const& _location, ASTPointer<ElementaryTypeName> const& _keyType,
            ASTPointer<TypeName> const& _valueType):
        TypeName(_location), m_keyType(_keyType), m_valueType(_valueType) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual std::shared_ptr<Type> toType() override { return Type::fromMapping(*this); }

private:
    ASTPointer<ElementaryTypeName> m_keyType;
    ASTPointer<TypeName> m_valueType;
};

/// @}

/// Statements
/// @{


/// Abstract base class for statements.
class Statement: public ASTNode
{
public:
    explicit Statement(Location const& _location): ASTNode(_location) {}
    virtual void accept(ASTVisitor& _visitor) override;

    //! Check all type requirements, throws exception if some requirement is not met.
    //! This includes checking that operators are applicable to their arguments but also that
    //! the number of function call arguments matches the number of formal parameters and so forth.
    virtual void checkTypeRequirements() = 0;

protected:
    //! Helper function, check that the inferred type for @a _expression is @a _expectedType or at
    //! least implicitly convertible to @a _expectedType. If not, throw exception.
    void expectType(Expression& _expression, Type const& _expectedType);
};

/// Brace-enclosed block containing zero or more statements.
class Block: public Statement
{
public:
    Block(Location const& _location, std::vector<ASTPointer<Statement>> const& _statements):
        Statement(_location), m_statements(_statements) {}
    virtual void accept(ASTVisitor& _visitor) override;

    virtual void checkTypeRequirements() override;

private:
    std::vector<ASTPointer<Statement>> m_statements;
};

/// If-statement with an optional "else" part. Note that "else if" is modeled by having a new
/// if-statement as the false (else) body.
class IfStatement: public Statement
{
public:
    IfStatement(Location const& _location, ASTPointer<Expression> const& _condition,
                ASTPointer<Statement> const& _trueBody, ASTPointer<Statement> const& _falseBody):
        Statement(_location),
        m_condition(_condition), m_trueBody(_trueBody), m_falseBody(_falseBody) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;

private:
    ASTPointer<Expression> m_condition;
    ASTPointer<Statement> m_trueBody;
    ASTPointer<Statement> m_falseBody; //< "else" part, optional
};

/// Statement in which a break statement is legal.
/// @todo actually check this requirement.
class BreakableStatement: public Statement
{
public:
    BreakableStatement(Location const& _location): Statement(_location) {}
    virtual void accept(ASTVisitor& _visitor) override;
};

class WhileStatement: public BreakableStatement
{
public:
    WhileStatement(Location const& _location, ASTPointer<Expression> const& _condition,
                   ASTPointer<Statement> const& _body):
        BreakableStatement(_location), m_condition(_condition), m_body(_body) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;

private:
    ASTPointer<Expression> m_condition;
    ASTPointer<Statement> m_body;
};

class Continue: public Statement
{
public:
    Continue(Location const& _location): Statement(_location) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;
};

class Break: public Statement
{
public:
    Break(Location const& _location): Statement(_location) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;
};

class Return: public Statement
{
public:
    Return(Location const& _location, ASTPointer<Expression> _expression):
        Statement(_location), m_expression(_expression) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;

    void setFunctionReturnParameters(ParameterList& _parameters) { m_returnParameters = &_parameters; }

private:
    ASTPointer<Expression> m_expression; //< value to return, optional

    /// Pointer to the parameter list of the function, filled by the @ref NameAndTypeResolver.
    ParameterList* m_returnParameters;
};

/// Definition of a variable as a statement inside a function. It requires a type name (which can
/// also be "var") but the actual assignment can be missing.
/// Examples: var a = 2; uint256 a;
class VariableDefinition: public Statement
{
public:
    VariableDefinition(Location const& _location, ASTPointer<VariableDeclaration> _variable,
                       ASTPointer<Expression> _value):
        Statement(_location), m_variable(_variable), m_value(_value) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;

private:
    ASTPointer<VariableDeclaration> m_variable;
    ASTPointer<Expression> m_value; ///< the assigned value, can be missing
};

/// An expression, i.e. something that has a value (which can also be of type "void" in case
/// of function calls).
class Expression: public Statement
{
public:
    Expression(Location const& _location): Statement(_location) {}

    std::shared_ptr<Type const> const& getType() const { return m_type; }

protected:
    //! Inferred type of the expression, only filled after a call to checkTypeRequirements().
    std::shared_ptr<Type const> m_type;
};

/// @}

/// Expressions
/// @{

/// Assignment, can also be a compound assignment.
/// Examples: (a = 7 + 8) or (a *= 2)
class Assignment: public Expression
{
public:
    Assignment(Location const& _location, ASTPointer<Expression> const& _leftHandSide,
               Token::Value _assignmentOperator, ASTPointer<Expression> const& _rightHandSide):
        Expression(_location), m_leftHandSide(_leftHandSide),
        m_assigmentOperator(_assignmentOperator), m_rightHandSide(_rightHandSide) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;

    Expression& getLeftHandSide() const { return *m_leftHandSide; }
    Token::Value getAssignmentOperator() const { return m_assigmentOperator; }
    Expression& getRightHandSide() const { return *m_rightHandSide; }

private:
    ASTPointer<Expression> m_leftHandSide;
    Token::Value m_assigmentOperator;
    ASTPointer<Expression> m_rightHandSide;
};

/// Operation involving a unary operator, pre- or postfix.
/// Examples: ++i, delete x or !true
class UnaryOperation: public Expression
{
public:
    UnaryOperation(Location const& _location, Token::Value _operator,
                   ASTPointer<Expression> const& _subExpression, bool _isPrefix):
        Expression(_location), m_operator(_operator),
        m_subExpression(_subExpression), m_isPrefix(_isPrefix) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;

    Token::Value getOperator() const { return m_operator; }
    bool isPrefixOperation() const { return m_isPrefix; }

private:
    Token::Value m_operator;
    ASTPointer<Expression> m_subExpression;
    bool m_isPrefix;
};

/// Operation involving a binary operator.
/// Examples: 1 + 2, true && false or 1 <= 4
class BinaryOperation: public Expression
{
public:
    BinaryOperation(Location const& _location, ASTPointer<Expression> const& _left,
                    Token::Value _operator, ASTPointer<Expression> const& _right):
        Expression(_location), m_left(_left), m_operator(_operator), m_right(_right) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;

    Expression& getLeftExpression() const { return *m_left; }
    Expression& getRightExpression() const { return *m_right; }
    Token::Value getOperator() const { return m_operator; }

private:
    ASTPointer<Expression> m_left;
    Token::Value m_operator;
    ASTPointer<Expression> m_right;

    std::shared_ptr<Type const> m_commonType;
};

/// Can be ordinary function call, type cast or struct construction.
class FunctionCall: public Expression
{
public:
    FunctionCall(Location const& _location, ASTPointer<Expression> const& _expression,
                 std::vector<ASTPointer<Expression>> const& _arguments):
        Expression(_location), m_expression(_expression), m_arguments(_arguments) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;

    /// Returns true if this is not an actual function call, but an explicit type conversion
    /// or constructor call.
    bool isTypeConversion() const;

private:
    ASTPointer<Expression> m_expression;
    std::vector<ASTPointer<Expression>> m_arguments;
};

/// Access to a member of an object. Example: x.name
class MemberAccess: public Expression
{
public:
    MemberAccess(Location const& _location, ASTPointer<Expression> _expression,
                 ASTPointer<ASTString> const& _memberName):
        Expression(_location), m_expression(_expression), m_memberName(_memberName) {}
    virtual void accept(ASTVisitor& _visitor) override;
    const ASTString& getMemberName() const { return *m_memberName; }
    virtual void checkTypeRequirements() override;

private:
    ASTPointer<Expression> m_expression;
    ASTPointer<ASTString> m_memberName;
};

/// Index access to an array. Example: a[2]
class IndexAccess: public Expression
{
public:
    IndexAccess(Location const& _location, ASTPointer<Expression> const& _base,
                ASTPointer<Expression> const& _index):
        Expression(_location), m_base(_base), m_index(_index) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;

private:
    ASTPointer<Expression> m_base;
    ASTPointer<Expression> m_index;
};

/// Primary expression, i.e. an expression that do not be divided any further like a literal or
/// a variable reference.
class PrimaryExpression: public Expression
{
public:
    PrimaryExpression(Location const& _location): Expression(_location) {}
};

/// An identifier, i.e. a reference to a declaration by name like a variable or function.
class Identifier: public PrimaryExpression
{
public:
    Identifier(Location const& _location, ASTPointer<ASTString> const& _name):
        PrimaryExpression(_location), m_name(_name) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;

    ASTString const& getName() const { return *m_name; }

    void setReferencedDeclaration(Declaration& _referencedDeclaration) { m_referencedDeclaration = &_referencedDeclaration; }
    Declaration* getReferencedDeclaration() { return m_referencedDeclaration; }

private:
    ASTPointer<ASTString> m_name;

    //! Declaration the name refers to.
    Declaration* m_referencedDeclaration;
};

/// An elementary type name expression is used in expressions like "a = uint32(2)" to change the
/// type of an expression explicitly. Here, "uint32" is the elementary type name expression and
/// "uint32(2)" is a @ref FunctionCall.
class ElementaryTypeNameExpression: public PrimaryExpression
{
public:
    ElementaryTypeNameExpression(Location const& _location, Token::Value _typeToken):
        PrimaryExpression(_location), m_typeToken(_typeToken) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;

    Token::Value getTypeToken() const { return m_typeToken; }

private:
    Token::Value m_typeToken;
};

/// A literal string or number. @see Type::literalToBigEndian is used to actually parse its value.
class Literal: public PrimaryExpression
{
public:
    Literal(Location const& _location, Token::Value _token, ASTPointer<ASTString> const& _value):
        PrimaryExpression(_location), m_token(_token), m_value(_value) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void checkTypeRequirements() override;

    Token::Value getToken() const { return m_token; }
    /// @returns the non-parsed value of the literal
    ASTString const& getValue() const { return *m_value; }

private:
    Token::Value m_token;
    ASTPointer<ASTString> m_value;
};

/// @}

}
}