Using Caché Objects - InterSystems Documentation

##this Syntax
>Do ##class(Package.Class1)Class2Instance.Method(Args)
>Set localname = ##class(Package.Class1)Class2Instance.Method(Args)
You can cast both class methods and instance methods.
For example, suppose that two classes, MyClass.Up and MyClass.Down, both have Go methods.
The code of MyClass.Up.Go is:
Method Go()
{
Write "Go up.",!
}
and the code of MyClass.Down.Go is:
Method Go()
{
Write "Go down.",!
}
You can then create an instance of MyClass.Up and use it to invoke the MyClass.Down.Go
method:
>Set LocalInstance = ##class(MyClass.Up).%New()
>Do ##class(MyClass.Down)LocalInstance.Go()
Go down.
It is also valid to use ##class as part of an expression, as in
Write ##class(Class).Method(args)*2
without setting a variable equal to the return value.
A more generic way to refer to other methods are the $ZObjMethod and $ZObjClassMethod
functions, which are for instance and class methods, respectively. These provide a mechanism
for referring to packages, classes, and methods programmatically.
21.3 ##this Syntax
The ##this syntax provides a handle to the OREF of the current instance, such as for passing
it to another class or for another class to refer to the current instance's members. When an
instance refers to its own members, the .. syntax is preferred.
Note:
##this is case sensitive and must be in all lowercase.
Using Caché Objects 181