In particular, portable programs can control the implementation of, and obtain direct access to, slots with allocation :instance and type T. These are called directly accessible slots.

The class standard-object is the default direct superclass of the class standard-class. When an instance of the class standard-class is created, and no direct superclasses are explicitly specified, it defaults to the class standard-object. In this way, any behavior associated with the class standard-object will be inherited, directly or indirectly, by all instances of the class standard-class. A subclass of standard-class may have a different class as its default direct superclass, but that class must be a subclass of the class standard-object.

The same is true for funcallable-standard-class and funcallable-standard-object.

For each kind of program element there is a corresponding basic metaobject class. These are the classes: class, slot-definition, generic-function, method, and method-combination. [...]

The classes standard-class, standard-direct-slot-definition, standard-effective-slot-definition, standard-method, standard-reader-method, standard-writer-method, and standard-generic-function are called standard metaobject classes. [...]

For each kind of program element there is a corresponding basic metaobject class. These are the classes: class, slot-definition, generic-function, method, and method-combination. [...]

The classes standard-class, standard-direct-slot-definition, standard-effective-slot-definition, standard-method, standard-reader-method, standard-writer-method, and standard-generic-function are called standard metaobject classes. [...]

The classes standard-class, standard-direct-slot-definition, standard-effective-slot-definition, standard-method, standard-reader-method, standard-writer-method, and standard-generic-function are called standard metaobject classes. [...]

The classes standard-class, standard-direct-slot-definition, standard-effective-slot-definition, standard-method, standard-reader-method, standard-writer-method, and standard-generic-function are called standard metaobject classes. [...]

For each kind of program element there is a corresponding basic metaobject class. These are the classes: class, slot-definition, generic-function, method, and method-combination. [...]

The classes standard-class, standard-direct-slot-definition, standard-effective-slot-definition, standard-method, standard-reader-method, standard-writer-method, and standard-generic-function are called standard metaobject classes. [...]

The classes standard-class, standard-direct-slot-definition, standard-effective-slot-definition, standard-method, standard-reader-method, standard-writer-method, and standard-generic-function are called standard metaobject classes. [...]

For each kind of program element there is a corresponding basic metaobject class. These are the classes: class, slot-definition, generic-function, method, and method-combination. [...]

The class specializer captures only the most basic behavior of method specializers, and is not itself intended to be instantiated. The class class is a direct subclass of specializer reflecting the property that classes by themselves can be used as method specializers. [...]

For each kind of program element there is a corresponding basic metaobject class. These are the classes: class, slot-definition, generic-function, method, and method-combination. [...]

[...] The class class is a direct subclass of specializer reflecting the property that classes by themselves can be used as method specializers. [...]

[...] The class eql-specializer is used for eql specializers.

[...] In the case of eql specializers, it will be an eql-specializer metaobject obtained by calling intern-eql-specializer on the result of evaluating the eql specializer form in the lexical environment of the defmethod form.

The classes standard-class, standard-direct-slot-definition, standard-effective-slot-definition, standard-method, standard-reader-method, standard-writer-method, and standard-generic-function are called standard metaobject classes. [...]

[...]

The class standard-object is the default direct superclass of the class standard-class. When an instance of the class standard-class is created, and no direct superclasses are explicitly specified, it defaults to the class standard-object. In this way, any behavior associated with the class standard-object will be inherited, directly or indirectly, by all instances of the class standard-class. A subclass of standard-class may have a different class as its default direct superclass, but that class must be a subclass of the class standard-object.

[...] The exact point at which finalize-inheritance is called depends on the class of the class metaobject; for standard-class it is called sometime after all the class' superclasses are defined, but no later than when the first instance of the class is allocated (by allocate-instance).

Given the location of a directly accessible slot, the value of that slot in an instance can be accessed with the appropriate accessor. For standard-class, this accessor is the function standard-instance-access. [...]

[...]

(defclass ordered-class (standard-class)
[...]
                  

The classes built-in-class, funcallable-standard-class and forward-referenced-class are special-purpose class metaobject classes. [...] The class funcallable-standard-class provides a special kind of instances described in the section called Funcallable Instances. [...]

[...]

The same is true for funcallable-standard-class and funcallable-standard-object.

Given the location of a directly accessible slot, the value of that slot in an instance can be accessed with the appropriate accessor. [...] For funcallable-standard-class, this accessor is the function funcallable-standard-instance-access. [...]

Instances of classes which are themselves instances of funcallable-standard-class or one of its subclasses are called funcallable instances. Funcallable instances can only be created by allocate-instance (class funcallable-standard-class).

[...]

(defclass constructor ()
     ((name :initarg :name :accessor constructor-name)
      (fields :initarg :fields :accessor constructor-fields))
  (:metaclass funcallable-standard-class))

[...]
                  

The classes built-in-class, funcallable-standard-class and forward-referenced-class are special-purpose class metaobject classes. Built-in classes are instances of the class built-in-class. [...]

The classes built-in-class, funcallable-standard-class and forward-referenced-class are special-purpose class metaobject classes. [...] When the definition of a class references another class which has not yet been defined, an instance of forward-referenced-class is used as a stand-in until the class is actually defined.