class.0

Object-Oriented Programming With ANSI-C这本书中的源代码!找了很久

Class(3)                                                 Class(3)


NAME
       Class  Class: Object - root metaclass

SYNOPSIS
       Object
           Class
       new(Class(), name, superclass, size, selector, tag, method, ... , 0);
       Object @ allocate (const self)
       const Class @ super (const self)
       const char * nameOf (const self)

DESCRIPTION
       A  metaclass  object  describes a class, i.e., it contains
       the class name,  a  pointer  to  the  class'  super  class
       description,  the  size  of  an  object  in the class, and
       information about all dynamically linked methods which can
       be applied to objects of the class.  This information con-
       sists of a pointer to the selector function, a tag  string
       for  the  respondsTo  method  (which  may be empty), and a
       pointer to the actual method function for objects  of  the
       class.

       A metaclass is a collection of metaclass objects which all
       contain the same variety of method informations, where, of
       course, each metaclass object may point to different meth-
       ods.  A metaclass description describes a metaclass.

       Class is the root metaclass.  There is a metaclass  object
       Class  which  describes  the metaclass Class.  Every other
       metaclass X is described by some other metaclass object  X
       which is a member of Class.

       The  metaclass  Class  contains  a metaclass object Object
       which describes the root class Object.   A  new  class  Y,
       which  has the same dynamically bound methods as the class
       Object, is described by a metaclass object Y, which  is  a
       member of Class.

       A  new  class  Z, which has more dynamically bound methods
       than Object, requires a metaclass object  Z,  which  is  a
       member  of  a  new  metaclass M.  This new metaclass has a
       metaclass description M, which is a member of Class.

       The Class constructor is used to build new class  descrip-
       tion objects like Y and metaclass description objects like
       M.  The M constructor is used to build new class  descrip-
       tion  objects  like  Z.   The Y constructor builds objects
       which are members of class Y, and the Z constructor builds
       objects in class Z.

       allocate  reserves  memory  for  an object of its argument
       class and installs this class  as  the  class  description
       pointer.   Unless  overwritten,  new  calls  allocate  and
       applies ctor to the result.  retrieve calls  allocate  and



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Class(3)                                                 Class(3)


       applies geto to the result.

       super returns the superclass from a class description.

       nameOf returns the name from a class description.

       The  Class  constructor  ctor  handles method inheritance.
       Only information about overwritten  methods  needs  to  be
       passed to new.  The information consists of the address of
       the selector to locate the method, a tag string which  may
       be  empty,  and the address of the new method.  The method
       information tuples may appear in  any  order  of  methods;
       zero in place of a selector terminates the list.

       delete,  dtor, and geto are inoperative for class descrip-
       tions.

       Class descriptions are only accessed by means of functions
       which initialize the description during the first call.

SEE ALSO
       ooc(1), retrieve(2)



































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