path: root/libsolidity/ast/AST.h

/*
    This file is part of solidity.

    solidity 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.

    solidity 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 solidity.  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 <libevmasm/SourceLocation.h>
#include <libevmasm/Instruction.h>
#include <libsolidity/interface/Utils.h>
#include <libsolidity/ast/ASTForward.h>
#include <libsolidity/parsing/Token.h>
#include <libsolidity/ast/Types.h>
#include <libsolidity/interface/Exceptions.h>
#include <libsolidity/ast/ASTAnnotations.h>
#include <json/json.h>

namespace dev
{
namespace solidity
{

class ASTVisitor;
class ASTConstVisitor;


/**
 * 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(SourceLocation const& _location);
    virtual ~ASTNode();

    /// @returns an identifier of this AST node that is unique for a single compilation run.
    size_t id() const { return m_id; }
    /// Resets the global ID counter. This invalidates all previous IDs.
    static void resetID();

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

    /// @returns a copy of the vector containing only the nodes which derive from T.
    template <class _T>
    static std::vector<_T const*> filteredNodes(std::vector<ASTPointer<ASTNode>> const& _nodes);

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

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

    ///@todo make this const-safe by providing a different way to access the annotation
    virtual ASTAnnotation& annotation() const;

    ///@{
    ///@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); }
    ///@}

protected:
    size_t const m_id = 0;
    /// Annotation - is specialised in derived classes, is created upon request (because of polymorphism).
    mutable ASTAnnotation* m_annotation = nullptr;

private:
    SourceLocation m_location;
};

template <class _T>
std::vector<_T const*> ASTNode::filteredNodes(std::vector<ASTPointer<ASTNode>> const& _nodes)
{
    std::vector<_T const*> ret;
    for (auto const& n: _nodes)
        if (auto const* nt = dynamic_cast<_T const*>(n.get()))
            ret.push_back(nt);
    return ret;
}

/**
 * Source unit containing import directives and contract definitions.
 */
class SourceUnit: public ASTNode
{
public:
    SourceUnit(SourceLocation const& _location, std::vector<ASTPointer<ASTNode>> const& _nodes):
        ASTNode(_location), m_nodes(_nodes) {}

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;
    virtual SourceUnitAnnotation& annotation() const override;

    std::vector<ASTPointer<ASTNode>> nodes() const { return m_nodes; }

private:
    std::vector<ASTPointer<ASTNode>> m_nodes;
};

/**
 * Abstract AST class for a declaration (contract, function, struct, variable, import directive).
 */
class Declaration: public ASTNode
{
public:
    /// Visibility ordered from restricted to unrestricted.
    enum class Visibility { Default, Private, Internal, Public, External };

    Declaration(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _name,
        Visibility _visibility = Visibility::Default
    ):
        ASTNode(_location), m_name(_name), m_visibility(_visibility), m_scope(nullptr) {}

    /// @returns the declared name.
    ASTString const& name() const { return *m_name; }
    Visibility visibility() const { return m_visibility == Visibility::Default ? defaultVisibility() : m_visibility; }
    bool isPublic() const { return visibility() >= Visibility::Public; }
    virtual bool isVisibleInContract() const { return visibility() != Visibility::External; }
    bool isVisibleInDerivedContracts() const { return isVisibleInContract() && visibility() >= Visibility::Internal; }

    /// @returns the scope this declaration resides in. Can be nullptr if it is the global scope.
    /// Available only after name and type resolution step.
    ASTNode const* scope() const { return m_scope; }
    void setScope(ASTNode const* _scope) { m_scope = _scope; }

    /// @returns the source name this declaration is present in.
    /// Can be combined with annotation().canonicalName to form a globally unique name.
    std::string sourceUnitName() const;
    std::string fullyQualifiedName() const { return sourceUnitName() + ":" + name(); }

    virtual bool isLValue() const { return false; }
    virtual bool isPartOfExternalInterface() const { return false; }

    /// @returns the type of expressions referencing this declaration.
    /// The current contract has to be given since this context can change the type, especially of
    /// contract types.
    /// This can only be called once types of variable declarations have already been resolved.
    virtual TypePointer type() const = 0;

    /// @param _internal false indicates external interface is concerned, true indicates internal interface is concerned.
    /// @returns null when it is not accessible as a function.
    virtual std::shared_ptr<FunctionType> functionType(bool /*_internal*/) const { return {}; }

protected:
    virtual Visibility defaultVisibility() const { return Visibility::Public; }

private:
    ASTPointer<ASTString> m_name;
    Visibility m_visibility;
    ASTNode const* m_scope;
};

/**
 * Pragma directive, only version requirements in the form `pragma solidity "^0.4.0";` are
 * supported for now.
 */
class PragmaDirective: public ASTNode
{
public:
    PragmaDirective(
        SourceLocation const& _location,
        std::vector<Token::Value> const& _tokens,
        std::vector<ASTString> const& _literals
    ): ASTNode(_location), m_tokens(_tokens), m_literals(_literals)
    {}

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    std::vector<Token::Value> const& tokens() const { return m_tokens; }
    std::vector<ASTString> const& literals() const { return m_literals; }

private:

    /// Sequence of tokens following the "pragma" keyword.
    std::vector<Token::Value> m_tokens;
    /// Sequence of literals following the "pragma" keyword.
    std::vector<ASTString> m_literals;
};

/**
 * Import directive for referencing other files / source objects.
 * Example: import "abc.sol" // imports all symbols of "abc.sol" into current scope
 * Source objects are identified by a string which can be a file name but does not have to be.
 * Other ways to use it:
 * import "abc" as x; // creates symbol "x" that contains all symbols in "abc"
 * import * as x from "abc"; // same as above
 * import {a as b, c} from "abc"; // creates new symbols "b" and "c" referencing "a" and "c" in "abc", respectively.
 */
class ImportDirective: public Declaration
{
public:
    ImportDirective(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _path,
        ASTPointer<ASTString> const& _unitAlias,
        std::vector<std::pair<ASTPointer<Identifier>, ASTPointer<ASTString>>>&& _symbolAliases
    ):
        Declaration(_location, _unitAlias),
        m_path(_path),
        m_symbolAliases(_symbolAliases)
    { }

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    ASTString const& path() const { return *m_path; }
    std::vector<std::pair<ASTPointer<Identifier>, ASTPointer<ASTString>>> const& symbolAliases() const
    {
        return m_symbolAliases;
    }
    virtual ImportAnnotation& annotation() const override;

    virtual TypePointer type() const override;

private:
    ASTPointer<ASTString> m_path;
    /// The aliases for the specific symbols to import. If non-empty import the specific symbols.
    /// If the second component is empty, import the identifier unchanged.
    /// If both m_unitAlias and m_symbolAlias are empty, import all symbols into the current scope.
    std::vector<std::pair<ASTPointer<Identifier>, ASTPointer<ASTString>>> m_symbolAliases;
};

/**
 * Abstract class that is added to each AST node that can store local variables.
 */
class VariableScope
{
public:
    void addLocalVariable(VariableDeclaration const& _localVariable) { m_localVariables.push_back(&_localVariable); }
    std::vector<VariableDeclaration const*> const& localVariables() const { return m_localVariables; }

private:
    std::vector<VariableDeclaration const*> m_localVariables;
};

/**
 * Abstract class that is added to each AST node that can receive documentation.
 */
class Documented
{
public:
    explicit Documented(ASTPointer<ASTString> const& _documentation): m_documentation(_documentation) {}

    /// @return A shared pointer of an ASTString.
    /// Can contain a nullptr in which case indicates absence of documentation
    ASTPointer<ASTString> const& documentation() const { return m_documentation; }

protected:
    ASTPointer<ASTString> m_documentation;
};

/**
 * Abstract class that is added to AST nodes that can be marked as not being fully implemented
 */
class ImplementationOptional
{
public:
    explicit ImplementationOptional(bool _implemented): m_implemented(_implemented) {}

    /// @return whether this node is fully implemented or not
    bool isImplemented() const { return m_implemented; }

protected:
    bool m_implemented;
};

/// @}

/**
 * Definition of a contract or library. 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 Documented
{
public:
    enum class ContractKind { Interface, Contract, Library };

    ContractDefinition(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _name,
        ASTPointer<ASTString> const& _documentation,
        std::vector<ASTPointer<InheritanceSpecifier>> const& _baseContracts,
        std::vector<ASTPointer<ASTNode>> const& _subNodes,
        ContractKind _contractKind = ContractKind::Contract
    ):
        Declaration(_location, _name),
        Documented(_documentation),
        m_baseContracts(_baseContracts),
        m_subNodes(_subNodes),
        m_contractKind(_contractKind)
    {}

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    std::vector<ASTPointer<InheritanceSpecifier>> const& baseContracts() const { return m_baseContracts; }
    std::vector<ASTPointer<ASTNode>> const& subNodes() const { return m_subNodes; }
    std::vector<UsingForDirective const*> usingForDirectives() const { return filteredNodes<UsingForDirective>(m_subNodes); }
    std::vector<StructDefinition const*> definedStructs() const { return filteredNodes<StructDefinition>(m_subNodes); }
    std::vector<EnumDefinition const*> definedEnums() const { return filteredNodes<EnumDefinition>(m_subNodes); }
    std::vector<VariableDeclaration const*> stateVariables() const { return filteredNodes<VariableDeclaration>(m_subNodes); }
    std::vector<ModifierDefinition const*> functionModifiers() const { return filteredNodes<ModifierDefinition>(m_subNodes); }
    std::vector<FunctionDefinition const*> definedFunctions() const { return filteredNodes<FunctionDefinition>(m_subNodes); }
    std::vector<EventDefinition const*> events() const { return filteredNodes<EventDefinition>(m_subNodes); }
    std::vector<EventDefinition const*> const& interfaceEvents() const;
    bool isLibrary() const { return m_contractKind == ContractKind::Library; }

    /// @returns a map of canonical function signatures to FunctionDefinitions
    /// as intended for use by the ABI.
    std::map<FixedHash<4>, FunctionTypePointer> interfaceFunctions() const;
    std::vector<std::pair<FixedHash<4>, FunctionTypePointer>> const& interfaceFunctionList() const;

    /// @returns a list of the inheritable members of this contract
    std::vector<Declaration const*> const& inheritableMembers() const;

    /// Returns the constructor or nullptr if no constructor was specified.
    FunctionDefinition const* constructor() const;
    /// @returns true iff the constructor of this contract is public (or non-existing).
    bool constructorIsPublic() const;
    /// Returns the fallback function or nullptr if no fallback function was specified.
    FunctionDefinition const* fallbackFunction() const;

    Json::Value const& userDocumentation() const;
    void setUserDocumentation(Json::Value const& _userDocumentation);

    Json::Value const& devDocumentation() const;
    void setDevDocumentation(Json::Value const& _devDocumentation);

    virtual TypePointer type() const override;

    virtual ContractDefinitionAnnotation& annotation() const override;

    ContractKind contractKind() const { return m_contractKind; }

private:
    std::vector<ASTPointer<InheritanceSpecifier>> m_baseContracts;
    std::vector<ASTPointer<ASTNode>> m_subNodes;
    ContractKind m_contractKind;

    // parsed Natspec documentation of the contract.
    Json::Value m_userDocumentation;
    Json::Value m_devDocumentation;

    std::vector<ContractDefinition const*> m_linearizedBaseContracts;
    mutable std::unique_ptr<std::vector<std::pair<FixedHash<4>, FunctionTypePointer>>> m_interfaceFunctionList;
    mutable std::unique_ptr<std::vector<EventDefinition const*>> m_interfaceEvents;
    mutable std::unique_ptr<std::vector<Declaration const*>> m_inheritableMembers;
};

class InheritanceSpecifier: public ASTNode
{
public:
    InheritanceSpecifier(
        SourceLocation const& _location,
        ASTPointer<UserDefinedTypeName> const& _baseName,
        std::vector<ASTPointer<Expression>> _arguments
    ):
        ASTNode(_location), m_baseName(_baseName), m_arguments(_arguments) {}

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    UserDefinedTypeName const& name() const { return *m_baseName; }
    std::vector<ASTPointer<Expression>> const& arguments() const { return m_arguments; }

private:
    ASTPointer<UserDefinedTypeName> m_baseName;
    std::vector<ASTPointer<Expression>> m_arguments;
};

/**
 * `using LibraryName for uint` will attach all functions from the library LibraryName
 * to `uint` if the first parameter matches the type. `using LibraryName for *` attaches
 * the function to any matching type.
 */
class UsingForDirective: public ASTNode
{
public:
    UsingForDirective(
        SourceLocation const& _location,
        ASTPointer<UserDefinedTypeName> const& _libraryName,
        ASTPointer<TypeName> const& _typeName
    ):
        ASTNode(_location), m_libraryName(_libraryName), m_typeName(_typeName) {}

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    UserDefinedTypeName const& libraryName() const { return *m_libraryName; }
    /// @returns the type name the library is attached to, null for `*`.
    TypeName const* typeName() const { return m_typeName.get(); }

private:
    ASTPointer<UserDefinedTypeName> m_libraryName;
    ASTPointer<TypeName> m_typeName;
};

class StructDefinition: public Declaration
{
public:
    StructDefinition(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _name,
        std::vector<ASTPointer<VariableDeclaration>> const& _members
    ):
        Declaration(_location, _name), m_members(_members) {}

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    std::vector<ASTPointer<VariableDeclaration>> const& members() const { return m_members; }

    virtual TypePointer type() const override;

    virtual TypeDeclarationAnnotation& annotation() const override;

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

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

    std::vector<ASTPointer<EnumValue>> const& members() const { return m_members; }

    virtual TypePointer type() const override;

    virtual TypeDeclarationAnnotation& annotation() const override;

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

/**
 * Declaration of an Enum Value
 */
class EnumValue: public Declaration
{
public:
    EnumValue(SourceLocation const& _location, ASTPointer<ASTString> const& _name):
        Declaration(_location, _name) {}

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    virtual TypePointer type() const override;
};

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

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

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

/**
 * Base class for all nodes that define function-like objects, i.e. FunctionDefinition,
 * EventDefinition and ModifierDefinition.
 */
class CallableDeclaration: public Declaration, public VariableScope
{
public:
    CallableDeclaration(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _name,
        Declaration::Visibility _visibility,
        ASTPointer<ParameterList> const& _parameters,
        ASTPointer<ParameterList> const& _returnParameters = ASTPointer<ParameterList>()
    ):
        Declaration(_location, _name, _visibility),
        m_parameters(_parameters),
        m_returnParameters(_returnParameters)
    {
    }

    std::vector<ASTPointer<VariableDeclaration>> const& parameters() const { return m_parameters->parameters(); }
    ParameterList const& parameterList() const { return *m_parameters; }
    ASTPointer<ParameterList> const& returnParameterList() const { return m_returnParameters; }

protected:
    ASTPointer<ParameterList> m_parameters;
    ASTPointer<ParameterList> m_returnParameters;
};

class FunctionDefinition: public CallableDeclaration, public Documented, public ImplementationOptional
{
public:
    FunctionDefinition(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _name,
        Declaration::Visibility _visibility,
        bool _isConstructor,
        ASTPointer<ASTString> const& _documentation,
        ASTPointer<ParameterList> const& _parameters,
        bool _isDeclaredConst,
        std::vector<ASTPointer<ModifierInvocation>> const& _modifiers,
        ASTPointer<ParameterList> const& _returnParameters,
        bool _isPayable,
        ASTPointer<Block> const& _body
    ):
        CallableDeclaration(_location, _name, _visibility, _parameters, _returnParameters),
        Documented(_documentation),
        ImplementationOptional(_body != nullptr),
        m_isConstructor(_isConstructor),
        m_isDeclaredConst(_isDeclaredConst),
        m_isPayable(_isPayable),
        m_functionModifiers(_modifiers),
        m_body(_body)
    {}

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    bool isConstructor() const { return m_isConstructor; }
    bool isDeclaredConst() const { return m_isDeclaredConst; }
    bool isPayable() const { return m_isPayable; }
    std::vector<ASTPointer<ModifierInvocation>> const& modifiers() const { return m_functionModifiers; }
    std::vector<ASTPointer<VariableDeclaration>> const& returnParameters() const { return m_returnParameters->parameters(); }
    Block const& body() const { solAssert(m_body, ""); return *m_body; }
    virtual bool isVisibleInContract() const override
    {
        return Declaration::isVisibleInContract() && !isConstructor() && !name().empty();
    }
    virtual bool isPartOfExternalInterface() const override { return isPublic() && !m_isConstructor && !name().empty(); }

    /// @returns the external signature of the function
    /// That consists of the name of the function followed by the types of the
    /// arguments separated by commas all enclosed in parentheses without any spaces.
    std::string externalSignature() const;

    virtual TypePointer type() const override;

    /// @param _internal false indicates external interface is concerned, true indicates internal interface is concerned.
    /// @returns null when it is not accessible as a function.
    virtual std::shared_ptr<FunctionType> functionType(bool /*_internal*/) const override;

    virtual FunctionDefinitionAnnotation& annotation() const override;

private:
    bool m_isConstructor;
    bool m_isDeclaredConst;
    bool m_isPayable;
    std::vector<ASTPointer<ModifierInvocation>> m_functionModifiers;
    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 bodies.
 */
class VariableDeclaration: public Declaration
{
public:
    enum Location { Default, Storage, Memory };

    VariableDeclaration(
        SourceLocation const& _sourceLocation,
        ASTPointer<TypeName> const& _type,
        ASTPointer<ASTString> const& _name,
        ASTPointer<Expression> _value,
        Visibility _visibility,
        bool _isStateVar = false,
        bool _isIndexed = false,
        bool _isConstant = false,
        Location _referenceLocation = Location::Default
    ):
        Declaration(_sourceLocation, _name, _visibility),
        m_typeName(_type),
        m_value(_value),
        m_isStateVariable(_isStateVar),
        m_isIndexed(_isIndexed),
        m_isConstant(_isConstant),
        m_location(_referenceLocation) {}

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    TypeName* typeName() const { return m_typeName.get(); }
    ASTPointer<Expression> const& value() const { return m_value; }

    virtual bool isLValue() const override;
    virtual bool isPartOfExternalInterface() const override { return isPublic(); }

    bool isLocalVariable() const { return !!dynamic_cast<CallableDeclaration const*>(scope()); }
    /// @returns true if this variable is a parameter or return parameter of a function.
    bool isCallableParameter() const;
    /// @returns true if this variable is a parameter (not return parameter) of an external function.
    bool isExternalCallableParameter() const;
    /// @returns true if the type of the variable does not need to be specified, i.e. it is declared
    /// in the body of a function or modifier.
    bool canHaveAutoType() const;
    bool isStateVariable() const { return m_isStateVariable; }
    bool isIndexed() const { return m_isIndexed; }
    bool isConstant() const { return m_isConstant; }
    Location referenceLocation() const { return m_location; }

    virtual TypePointer type() const override;

    /// @param _internal false indicates external interface is concerned, true indicates internal interface is concerned.
    /// @returns null when it is not accessible as a function.
    virtual std::shared_ptr<FunctionType> functionType(bool /*_internal*/) const override;

    virtual VariableDeclarationAnnotation& annotation() const override;

protected:
    Visibility defaultVisibility() const override { return Visibility::Internal; }

private:
    ASTPointer<TypeName> m_typeName; ///< can be empty ("var")
    /// Initially assigned value, can be missing. For local variables, this is stored inside
    /// VariableDeclarationStatement and not here.
    ASTPointer<Expression> m_value;
    bool m_isStateVariable; ///< Whether or not this is a contract state variable
    bool m_isIndexed; ///< Whether this is an indexed variable (used by events).
    bool m_isConstant; ///< Whether the variable is a compile-time constant.
    Location m_location; ///< Location of the variable if it is of reference type.
};

/**
 * Definition of a function modifier.
 */
class ModifierDefinition: public CallableDeclaration, public Documented
{
public:
    ModifierDefinition(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _name,
        ASTPointer<ASTString> const& _documentation,
        ASTPointer<ParameterList> const& _parameters,
        ASTPointer<Block> const& _body
    ):
        CallableDeclaration(_location, _name, Visibility::Default, _parameters),
        Documented(_documentation),
        m_body(_body)
    {
    }

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    Block const& body() const { return *m_body; }

    virtual TypePointer type() const override;

    virtual ModifierDefinitionAnnotation& annotation() const override;

private:
    ASTPointer<Block> m_body;
};

/**
 * Invocation/usage of a modifier in a function header or a base constructor call.
 */
class ModifierInvocation: public ASTNode
{
public:
    ModifierInvocation(
        SourceLocation const& _location,
        ASTPointer<Identifier> const& _name,
        std::vector<ASTPointer<Expression>> _arguments
    ):
        ASTNode(_location), m_modifierName(_name), m_arguments(_arguments) {}

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    ASTPointer<Identifier> const& name() const { return m_modifierName; }
    std::vector<ASTPointer<Expression>> const& arguments() const { return m_arguments; }

private:
    ASTPointer<Identifier> m_modifierName;
    std::vector<ASTPointer<Expression>> m_arguments;
};

/**
 * Definition of a (loggable) event.
 */
class EventDefinition: public CallableDeclaration, public Documented
{
public:
    EventDefinition(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _name,
        ASTPointer<ASTString> const& _documentation,
        ASTPointer<ParameterList> const& _parameters,
        bool _anonymous = false
    ):
        CallableDeclaration(_location, _name, Visibility::Default, _parameters),
        Documented(_documentation),
        m_anonymous(_anonymous)
    {
    }

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    bool isAnonymous() const { return m_anonymous; }

    virtual TypePointer type() const override;
    virtual std::shared_ptr<FunctionType> functionType(bool /*_internal*/) const override;

    virtual EventDefinitionAnnotation& annotation() const override;

private:
    bool m_anonymous = false;
};

/**
 * Pseudo AST node that is used as declaration for "this", "msg", "tx", "block" and the global
 * functions when such an identifier is encountered. Will never have a valid location in the source code.
 */
class MagicVariableDeclaration: public Declaration
{
public:
    MagicVariableDeclaration(ASTString const& _name, std::shared_ptr<Type const> const& _type):
        Declaration(SourceLocation(), std::make_shared<ASTString>(_name)), m_type(_type) {}
    virtual void accept(ASTVisitor&) override
    {
        BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("MagicVariableDeclaration used inside real AST."));
    }
    virtual void accept(ASTConstVisitor&) const override
    {
        BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("MagicVariableDeclaration used inside real AST."));
    }

    virtual TypePointer type() const override { return m_type; }

private:
    std::shared_ptr<Type const> m_type;
};

/// Types
/// @{

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

    virtual TypeNameAnnotation& annotation() const override;
};

/**
 * Any pre-defined type name represented by a single keyword, i.e. it excludes mappings,
 * contracts, functions, etc.
 */
class ElementaryTypeName: public TypeName
{
public:
    ElementaryTypeName(SourceLocation const& _location, ElementaryTypeNameToken const& _elem):
        TypeName(_location), m_type(_elem)
    {}

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    ElementaryTypeNameToken const& typeName() const { return m_type; }

private:
    ElementaryTypeNameToken m_type;
};

/**
 * Name referring to a user-defined type (i.e. a struct, contract, etc.).
 */
class UserDefinedTypeName: public TypeName
{
public:
    UserDefinedTypeName(SourceLocation const& _location, std::vector<ASTString> const& _namePath):
        TypeName(_location), m_namePath(_namePath) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    std::vector<ASTString> const& namePath() const { return m_namePath; }

    virtual UserDefinedTypeNameAnnotation& annotation() const override;

private:
    std::vector<ASTString> m_namePath;
};

/**
 * A literal function type. Its source form is "function (paramType1, paramType2) internal / external returns (retType1, retType2)"
 */
class FunctionTypeName: public TypeName
{
public:
    FunctionTypeName(
        SourceLocation const& _location,
        ASTPointer<ParameterList> const& _parameterTypes,
        ASTPointer<ParameterList> const& _returnTypes,
        Declaration::Visibility _visibility,
        bool _isDeclaredConst,
        bool _isPayable
    ):
        TypeName(_location), m_parameterTypes(_parameterTypes), m_returnTypes(_returnTypes),
        m_visibility(_visibility), m_isDeclaredConst(_isDeclaredConst), m_isPayable(_isPayable)
    {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    std::vector<ASTPointer<VariableDeclaration>> const& parameterTypes() const { return m_parameterTypes->parameters(); }
    std::vector<ASTPointer<VariableDeclaration>> const& returnParameterTypes() const { return m_returnTypes->parameters(); }
    ASTPointer<ParameterList> const& parameterTypeList() const { return m_parameterTypes; }
    ASTPointer<ParameterList> const& returnParameterTypeList() const { return m_returnTypes; }

    Declaration::Visibility visibility() const
    {
        return m_visibility == Declaration::Visibility::Default ? Declaration::Visibility::Internal : m_visibility;
    }
    bool isDeclaredConst() const { return m_isDeclaredConst; }
    bool isPayable() const { return m_isPayable; }

private:
    ASTPointer<ParameterList> m_parameterTypes;
    ASTPointer<ParameterList> m_returnTypes;
    Declaration::Visibility m_visibility;
    bool m_isDeclaredConst;
    bool m_isPayable;
};

/**
 * A mapping type. Its source form is "mapping('keyType' => 'valueType')"
 */
class Mapping: public TypeName
{
public:
    Mapping(
        SourceLocation 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 void accept(ASTConstVisitor& _visitor) const override;

    ElementaryTypeName const& keyType() const { return *m_keyType; }
    TypeName const& valueType() const { return *m_valueType; }

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

/**
 * An array type, can be "typename[]" or "typename[<expression>]".
 */
class ArrayTypeName: public TypeName
{
public:
    ArrayTypeName(
        SourceLocation const& _location,
        ASTPointer<TypeName> const& _baseType,
        ASTPointer<Expression> const& _length
    ):
        TypeName(_location), m_baseType(_baseType), m_length(_length) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    TypeName const& baseType() const { return *m_baseType; }
    Expression const* length() const { return m_length.get(); }

private:
    ASTPointer<TypeName> m_baseType;
    ASTPointer<Expression> m_length; ///< Length of the array, might be empty.
};

/// @}

/// Statements
/// @{


/**
 * Abstract base class for statements.
 */
class Statement: public ASTNode, public Documented
{
public:
    explicit Statement(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _docString
    ): ASTNode(_location), Documented(_docString) {}

    virtual StatementAnnotation& annotation() const override;
};

namespace assembly
{
// Forward-declaration to AsmData.h
struct Block;
}

/**
 * Inline assembly.
 */
class InlineAssembly: public Statement
{
public:
    InlineAssembly(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _docString,
        std::shared_ptr<assembly::Block> const& _operations
    ):
        Statement(_location, _docString), m_operations(_operations) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    assembly::Block const& operations() const { return *m_operations; }

    virtual InlineAssemblyAnnotation& annotation() const override;

private:
    std::shared_ptr<assembly::Block> m_operations;
};

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

    std::vector<ASTPointer<Statement>> const& statements() const { return m_statements; }

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

/**
 * Special placeholder statement denoted by "_" used in function modifiers. This is replaced by
 * the original function when the modifier is applied.
 */
class PlaceholderStatement: public Statement
{
public:
    explicit PlaceholderStatement(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _docString
    ): Statement(_location, _docString) {}

    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;
};

/**
 * 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(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _docString,
        ASTPointer<Expression> const& _condition,
        ASTPointer<Statement> const& _trueBody,
        ASTPointer<Statement> const& _falseBody
    ):
        Statement(_location, _docString),
        m_condition(_condition),
        m_trueBody(_trueBody),
        m_falseBody(_falseBody)
    {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    Expression const& condition() const { return *m_condition; }
    Statement const& trueStatement() const { return *m_trueBody; }
    /// @returns the "else" part of the if statement or nullptr if there is no "else" part.
    Statement const* falseStatement() const { return m_falseBody.get(); }

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

/**
 * Statement in which a break statement is legal (abstract class).
 */
class BreakableStatement: public Statement
{
public:
    explicit BreakableStatement(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _docString
    ): Statement(_location, _docString) {}
};

class WhileStatement: public BreakableStatement
{
public:
    WhileStatement(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _docString,
        ASTPointer<Expression> const& _condition,
        ASTPointer<Statement> const& _body,
        bool _isDoWhile
    ):
        BreakableStatement(_location, _docString), m_condition(_condition), m_body(_body),
        m_isDoWhile(_isDoWhile) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    Expression const& condition() const { return *m_condition; }
    Statement const& body() const { return *m_body; }
    bool isDoWhile() const { return m_isDoWhile; }

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

/**
 * For loop statement
 */
class ForStatement: public BreakableStatement
{
public:
    ForStatement(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _docString,
        ASTPointer<Statement> const& _initExpression,
        ASTPointer<Expression> const& _conditionExpression,
        ASTPointer<ExpressionStatement> const& _loopExpression,
        ASTPointer<Statement> const& _body
    ):
        BreakableStatement(_location, _docString),
        m_initExpression(_initExpression),
        m_condExpression(_conditionExpression),
        m_loopExpression(_loopExpression),
        m_body(_body)
    {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    Statement const* initializationExpression() const { return m_initExpression.get(); }
    Expression const* condition() const { return m_condExpression.get(); }
    ExpressionStatement const* loopExpression() const { return m_loopExpression.get(); }
    Statement const& body() const { return *m_body; }

private:
    /// For statement's initialization expresion. for(XXX; ; ). Can be empty
    ASTPointer<Statement> m_initExpression;
    /// For statement's condition expresion. for(; XXX ; ). Can be empty
    ASTPointer<Expression> m_condExpression;
    /// For statement's loop expresion. for(;;XXX). Can be empty
    ASTPointer<ExpressionStatement> m_loopExpression;
    /// The body of the loop
    ASTPointer<Statement> m_body;
};

class Continue: public Statement
{
public:
    explicit Continue(SourceLocation const& _location,  ASTPointer<ASTString> const& _docString):
        Statement(_location, _docString) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;
};

class Break: public Statement
{
public:
    explicit Break(SourceLocation const& _location, ASTPointer<ASTString> const& _docString):
        Statement(_location, _docString) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;
};

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

    Expression const* expression() const { return m_expression.get(); }

    virtual ReturnAnnotation& annotation() const override;

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

/**
 * @brief The Throw statement to throw that triggers a solidity exception(jump to ErrorTag)
 */
class Throw: public Statement
{
public:
    explicit Throw(SourceLocation const& _location, ASTPointer<ASTString> const& _docString):
        Statement(_location, _docString) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;
};

/**
 * 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;
 * As a second form, multiple variables can be declared, cannot have a type and must be assigned
 * right away. If the first or last component is unnamed, it can "consume" an arbitrary number
 * of components.
 * Examples: var (a, b) = f(); var (a,,,c) = g(); var (a,) = d();
 */
class VariableDeclarationStatement: public Statement
{
public:
    VariableDeclarationStatement(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _docString,
        std::vector<ASTPointer<VariableDeclaration>> const& _variables,
        ASTPointer<Expression> const& _initialValue
    ):
        Statement(_location, _docString), m_variables(_variables), m_initialValue(_initialValue) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    VariableDeclarationStatementAnnotation& annotation() const override;

    std::vector<ASTPointer<VariableDeclaration>> const& declarations() const { return m_variables; }
    Expression const* initialValue() const { return m_initialValue.get(); }

private:
    /// List of variables, some of which can be empty pointers (unnamed components).
    std::vector<ASTPointer<VariableDeclaration>> m_variables;
    /// The assigned expression / initial value.
    ASTPointer<Expression> m_initialValue;
};

/**
 * A statement that contains only an expression (i.e. an assignment, function call, ...).
 */
class ExpressionStatement: public Statement
{
public:
    ExpressionStatement(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _docString,
        ASTPointer<Expression> _expression
    ):
        Statement(_location, _docString), m_expression(_expression) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    Expression const& expression() const { return *m_expression; }

private:
    ASTPointer<Expression> m_expression;
};

/// @}

/// Expressions
/// @{

/**
 * An expression, i.e. something that has a value (which can also be of type "void" in case
 * of some function calls).
 * @abstract
 */
class Expression: public ASTNode
{
public:
    explicit Expression(SourceLocation const& _location): ASTNode(_location) {}

    ExpressionAnnotation& annotation() const override;
};

class Conditional: public Expression
{
public:
    Conditional(
        SourceLocation const& _location,
        ASTPointer<Expression> const& _condition,
        ASTPointer<Expression> const& _trueExpression,
        ASTPointer<Expression> const& _falseExpression
    ):
        Expression(_location),
        m_condition(_condition),
        m_trueExpression(_trueExpression),
        m_falseExpression(_falseExpression)
    {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    Expression const& condition() const { return *m_condition; }
    Expression const& trueExpression() const { return *m_trueExpression; }
    Expression const& falseExpression() const { return *m_falseExpression; }

private:
    ASTPointer<Expression> m_condition;
    ASTPointer<Expression> m_trueExpression;
    ASTPointer<Expression> m_falseExpression;
};

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

    Expression const& leftHandSide() const { return *m_leftHandSide; }
    Token::Value assignmentOperator() const { return m_assigmentOperator; }
    Expression const& rightHandSide() const { return *m_rightHandSide; }

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


/**
 * Tuple, parenthesized expression, or bracketed expression.
 * Examples: (1, 2), (x,), (x), (), [1, 2],
 * Individual components might be empty shared pointers (as in the second example).
 * The respective types in lvalue context are: 2-tuple, 2-tuple (with wildcard), type of x, 0-tuple
 * Not in lvalue context: 2-tuple, _1_-tuple, type of x, 0-tuple.
 */
class TupleExpression: public Expression
{
public:
    TupleExpression(
        SourceLocation const& _location,
        std::vector<ASTPointer<Expression>> const& _components,
        bool _isArray
    ):
        Expression(_location),
        m_components(_components),
        m_isArray(_isArray) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    std::vector<ASTPointer<Expression>> const& components() const { return m_components; }
    bool isInlineArray() const { return m_isArray; }

private:
    std::vector<ASTPointer<Expression>> m_components;
    bool m_isArray;
};

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

    Token::Value getOperator() const { return m_operator; }
    bool isPrefixOperation() const { return m_isPrefix; }
    Expression const& subExpression() const { return *m_subExpression; }

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(
        SourceLocation const& _location,
        ASTPointer<Expression> const& _left,
        Token::Value _operator,
        ASTPointer<Expression> const& _right
    ):
        Expression(_location), m_left(_left), m_operator(_operator), m_right(_right)
    {
        solAssert(Token::isBinaryOp(_operator) || Token::isCompareOp(_operator), "");
    }
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

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

    BinaryOperationAnnotation& annotation() const override;

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

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

    Expression const& expression() const { return *m_expression; }
    std::vector<ASTPointer<Expression const>> arguments() const { return {m_arguments.begin(), m_arguments.end()}; }
    std::vector<ASTPointer<ASTString>> const& names() const { return m_names; }

    virtual FunctionCallAnnotation& annotation() const override;

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

/**
 * Expression that creates a new contract or memory-array,
 * e.g. the "new SomeContract" part in "new SomeContract(1, 2)".
 */
class NewExpression: public Expression
{
public:
    NewExpression(
        SourceLocation const& _location,
        ASTPointer<TypeName> const& _typeName
    ):
        Expression(_location), m_typeName(_typeName) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    TypeName const& typeName() const { return *m_typeName; }

private:
    ASTPointer<TypeName> m_typeName;
};

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

    virtual MemberAccessAnnotation& annotation() const override;

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

/**
 * Index access to an array. Example: a[2]
 */
class IndexAccess: public Expression
{
public:
    IndexAccess(
        SourceLocation 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 accept(ASTConstVisitor& _visitor) const override;

    Expression const& baseExpression() const { return *m_base; }
    Expression const* indexExpression() const { return m_index.get(); }

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

/**
 * Primary expression, i.e. an expression that cannot be divided any further. Examples are literals
 * or variable references.
 */
class PrimaryExpression: public Expression
{
public:
    PrimaryExpression(SourceLocation 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(
        SourceLocation const& _location,
        ASTPointer<ASTString> const& _name
    ):
        PrimaryExpression(_location), m_name(_name) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

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

    virtual IdentifierAnnotation& annotation() const override;

private:
    ASTPointer<ASTString> m_name;
};

/**
 * 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(SourceLocation const& _location, ElementaryTypeNameToken const& _type):
        PrimaryExpression(_location), m_typeToken(_type)
    {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

    ElementaryTypeNameToken const& typeName() const { return m_typeToken; }

private:
    ElementaryTypeNameToken m_typeToken;
};

/**
 * A literal string or number. @see ExpressionCompiler::endVisit() is used to actually parse its value.
 */
class Literal: public PrimaryExpression
{
public:
    enum class SubDenomination
    {
        None = Token::Illegal,
        Wei = Token::SubWei,
        Szabo = Token::SubSzabo,
        Finney = Token::SubFinney,
        Ether = Token::SubEther,
        Second = Token::SubSecond,
        Minute = Token::SubMinute,
        Hour = Token::SubHour,
        Day = Token::SubDay,
        Week = Token::SubWeek,
        Year = Token::SubYear
    };
    Literal(
        SourceLocation const& _location,
        Token::Value _token,
        ASTPointer<ASTString> const& _value,
        SubDenomination _sub = SubDenomination::None
    ):
        PrimaryExpression(_location), m_token(_token), m_value(_value), m_subDenomination(_sub) {}
    virtual void accept(ASTVisitor& _visitor) override;
    virtual void accept(ASTConstVisitor& _visitor) const override;

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

    SubDenomination subDenomination() const { return m_subDenomination; }

    /// @returns true if this looks like a checksummed address.
    bool looksLikeAddress() const;
    /// @returns true if it passes the address checksum test.
    bool passesAddressChecksum() const;

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

/// @}


}
}