Member Metaobjects

Member metaobjects provide the ability of introspection and source-code translation of the members. They can be obtained by calling NthMember() or LookupMember() on a class metaobject. The following is the list of the member functions provided by the member metaobjects.

Public Members


ArgumentList()

Arguments()

FunctionBody()

GetUserAccessSpecifier()

GetUserArgumentModifiers(PtreeArray& modifiers)

GetUserMemberModifier()

IsConstructor()

IsDestructor()

IsFunction()

IsInline()

IsMutable()

IsPrivate()

IsProtected()

IsPublic()

IsPureVirtual()

IsStatic()

IsVirtual()

Member(Member&)

MemberInitializers()

Name()

NewArgumentList()

NewFunctionBody()

NewMemberInitializers()

NewName()

Nth()

SetArgumentList(Ptree* arglist)

SetFunctionBody(Ptree* body)

SetMemberInitializers(Ptree* init)

SetName(Ptree* name)

SetQualifiedName(Ptree* name)

Signature(TypeInfo& t)

Supplier()

Introspection

First, we show the member functions for introspection.

 Member(Member&)

This is a constructor to make a copy of a member metaobject.

Ptree* Name()

This returns the member name.

Ptree* ArgumentList()

This returns the formal argument list of the member. For example, if the member is int f(int, char*), then this function returns [[[int] [nil]] , [[char] [*]]]. If the member is a data member, this function returns nil.

Ptree* Arguments()

This returns the argument list of the member. Unlike ArgumentList(), the returned list does not include the types. It is a list of the argument names. If the member is int f(int p, char* q), then this function returns [p , q]. Even if the argument name is not given in the argument list, it is automatically filled by this function. In this case, the formal argument list of the member is also changed to include that argument name. If the member is a data member, this function returns nil.

Ptree* MemberInitializers()

This returns the member initializers if the member is a constructor. Otherwise, it returns nil. For example, if the member is:

X::X() : p(3), q(1) {
... }

Then this function returns [: [p ( [3] )] , [q ( [1] )]].

Ptree* FunctionBody()

This returns the function body if the member is a function. The returned text includes braces {}.

int Nth()

If the member is the i -th member, this returns i. Otherwise, if the member is not declared, it returns -1.

void Signature(TypeInfo& t)

This returns the type of the member in t. If the member is a member function, the returned type is the function type.

Class* Supplier()

This returns the class supplying this member. If the member is inherited from the base class, then the returned class is that base class.

bool IsConstructor()

This returns true if the member is a constructor.

bool IsDestructor()

This returns true if the member is a destructor.

bool IsFunction()

This returns true if the member is a member function.

bool IsPublic()

This returns true if the member is a public member.

bool IsProtected()

This returns true if the member is a protected member.

bool IsPrivate()

This returns true if the member is a private member.

bool IsStatic()

This returns true if the member is a static member.

bool IsMutable()

This returns true if the member is a mutable member.

bool IsInline()

This returns true if the member is a inline member function.

bool IsVirtual()

This returns true if the member is a virtual member function.

bool IsPureVirtual()

This returns true if the member is a pure virtual member function.

OpenC++ allows syntax extensions for access specifiers and argument lists. The following members are used for dealing with such syntax extensions.

Ptree* GetUserAccessSpecifier()

This returns an user-defined access specifier for the member. For example, suppose that sync is a user-defined keyword:

class Window {
public:
    void Move();
sync:
    void Resize();
};

Then GetUserAccessSpecifier() called on Resize() returns [sync :]. The user-defined access specifier is effective until another access specifier appears. For example:

class X {
public:
    void f1();     // public
sync:
    void f2();     // public, sync
private:
    void g1();     // private
sync:
    void g2();     // private, sync
};

The user-defined access specifiers are automatically eliminated. The programmer does not have to be concerned about it.

Ptree* GetUserMemberModifier()

This returns the member modifier for the member. If no member modifier is specified, this returns nil. The member modifier is automatically eliminated. The programmer does not have to be concerned about it.

bool GetUserArgumentModifiers(PtreeArray& modifiers)

This computes user-defined type modifiers attached to the argument types. If successful, it returns true and stores the result in modifiers. The result is a PtreeArray of user-defined type modifiers. The i-the element is one for the i-th argument. If no modifier is specified, the element is nil. For example, if ref is a user-defined type modifier,

class C {
public:
    void f(ref int p1, int p2);
};

Then GetUserArgumentModifiers() called on f returns an array { [ref], nil }.

All the user-defined type modifiers are automatically eliminated. The programmer does not have to be concerned about it.

Translation

The member metaobjects also provide functions for customizing the member. The changes are not actually reflected on the source-code translation until ChangeMember() or AppendMember() is called on the class metaobject.

void SetName(Ptree* name)

This changes the member name to name.

void SetQualifiedName(Ptree* name)

This changes the member name to name. Unlike SetName(), this function substitutes name for the member name including the qualified class name. It is useful in Class::TranslateMemberFunction(). For example, if the member is:

void Rect::Enlarge(int rx, int ry) { ... }

Then, SetQualifiedName(Ptree::Make("Point::Move")) changes this member to:

void Point::Move(int rx, int ry) { ... }

void SetArgumentList(Ptree* arglist)

This changes the formal argument list of the member function to arglist.

void SetMemberInitializers(Ptree* init)

This changes the member initializers of the constructor to init.

void SetFunctionBody(Ptree* body)

This changes the function body of the member to body.

The member functions for introspection such as Name() does not reflect the customization in the results. For example, Name() returns the original member name even if SetName() specifies a new name. To get the new value specified by the above functions such as SetName(), the following functions are used:

void NewName()

This returns the new member name substituted for the original one.

void NewArgumentList()

This returns the new argument list substituted for the original one.

void NewMemberInitializers()

This returns the new member initializers substituted for the original one.

void NewFunctionBody()

This returns the new function body substituted for the original one.

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