DOKK / manpages / debian 10 / tcl8.6-doc / oo_object.3tcl.en
object(3tcl) TclOO Commands object(3tcl) 







oo::object - root class of the class hierarchy








package require TclOO
oo::object method ?arg ...?








oo::object










The oo::object class is the root class of the object
    hierarchy; every object is an instance of this class. Since classes are
    themselves objects, they are instances of this class too. Objects are always
    referred to by their name, and may be renamed while maintaining their
    identity.


Instances of objects may be made with either the create or
    new methods of the oo::object object itself, or by invoking
    those methods on any of the subclass objects; see oo::class for more
    details. The configuration of individual objects (i.e., instance-specific
    methods, mixed-in classes, etc.) may be controlled with the
    oo::objdefine command.


Each object has a unique namespace associated with it, the
    instance namespace. This namespace holds all the instance variables of the
    object, and will be the current namespace whenever a method of the object is
    invoked (including a method of the class of the object). When the object is
    destroyed, its instance namespace is deleted. The instance namespace
    contains the object's my command, which may be used to invoke
    non-exported methods of the object or to create a reference to the object
    for the purpose of invocation which persists across renamings of the
  object.






The oo::object class does not define an explicit
    constructor.








The oo::object class does not define an explicit
    destructor.








The oo::object class supports the following exported
    methods:



  

  
This method destroys the object, obj, that it is invoked upon,
      invoking any destructors on the object's class in the process. It is
      equivalent to using rename to delete the object command. The result
      of this method is always the empty string.










The oo::object class supports the following non-exported
    methods:



  

  
This method concatenates the arguments, arg, as if with
      concat, and then evaluates the resulting script in the namespace
      that is uniquely associated with obj, returning the result of the
      evaluation.

  

  
This method is called when an attempt to invoke the method
      methodName on object obj fails. The arguments that the user
      supplied to the method are given as arg arguments. If
      methodName is absent, the object was invoked with no method name at
      all (or any other arguments). The default implementation (i.e., the one
      defined by the oo::object class) generates a suitable error,
      detailing what methods the object supports given whether the object was
      invoked by its public name or through the my command.

  

  
This method arranges for each variable called varName to be linked
      from the object obj's unique namespace into the caller's context.
      Thus, if it is invoked from inside a procedure then the namespace variable
      in the object is linked to the local variable in the procedure. Each
      varName argument must not have any namespace separators in it. The
      result is the empty string.

  

  
This method returns the globally qualified name of the variable
      varName in the unique namespace for the object obj.

  

  
This method is used by the oo::object command to copy the state of
      one object to another. It is responsible for copying the procedures and
      variables of the namespace of the source object (sourceObjectName)
      to the current object. It does not copy any other types of commands or any
      traces on the variables; that can be added if desired by overriding this
      method in a subclass.












This example demonstrates basic use of an object.






set obj [oo::object new]
$obj foo             → error "unknown method foo"
oo::objdefine $obj method foo {} {


    my variable count


    puts "bar[incr count]"
}
$obj foo             → prints "bar1"
$obj foo             → prints "bar2"
$obj variable count  → error "unknown method variable"
$obj destroy
$obj foo             → error "unknown command obj"










my(3tcl), oo::class(3tcl)








base class, class, object, root class







  

    0.1
    TclOO