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ActiveTcl User Guide |
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oo::copy - create copies of objects and classes
package require TclOO
oo::copy sourceObject ?targetObject?
The oo::copy command creates a copy of an object or class.
It takes the name of the object or class to be copied,
sourceObject, and optionally the name of the object or class
to create, targetObject, which will be resolved relative to
the current namespace if not an absolute qualified name. If
targetObject is omitted, a new name is chosen. The copied
object will be of the same class as the source object, and will
have all its per-object methods copied. If it is a class, it will
also have all the class methods in the class copied, but it will
not have any of its instances copied.
After the targetObject has been created and all
definitions of its configuration (e.g., methods, filters, mixins)
copied, the <cloned> method of targetObject
will be invoked, to allow for customization of the created object
such as installing related variable traces. The only argument given
will be sourceObject. The default implementation of this
method (in oo::object)
just copies the procedures and variables in the namespace of
sourceObject to the namespace of targetObject. If
this method call does not return a result that is successful (i.e.,
an error or other kind of exception) then the targetObject
will be deleted and an error returned.
The result of the oo::copy command will be the
fully-qualified name of the new object or class.
This example creates an object, copies it, modifies the source
object, and then demonstrates that the copied object is indeed a
copy.
oo::object create src
oo::objdefine src method msg {} {puts foo}
oo::copy src dst
oo::objdefine src method msg {} {puts bar}
src msg → prints "bar"
dst msg → prints "foo"
oo::class, oo::define, oo::object
clone, copy, duplication, object
Copyright © 1995-1997 Roger E. Critchlow Jr.
Copyright © 2007 Donal K. Fellows