Using Caché Objects - InterSystems Documentation

Kinds of Methods
• Code Methods
• Expression Methods
• Call Methods
• Method Generators
The various method types control how the Caché class compiler interprets the Implementation
of the method.
6.7.1 Code Methods
A code method is a method whose implementation is simply lines of code. This is the most
typical type of method and is the default.
For instance, the following method defines a Speak code method for the Dog class:
Class MyApp.Dog Extends %Persistent [ClassType = persistent]
{
Method Speak() As %String
{
Quit "Woof, Woof"
}
}
The method code can contain any valid Caché ObjectScript code (including embedded SQL
and embedded HTML) or Basic code (depending on the method's Language keyword).
Assuming dog refers to a Dog object, you could invoke this method as follows:
Write dog.Speak()
// yields: Woof, Woof
6.7.2 Expression Methods
An expression method is a method that may be replaced by the class compiler, in certain
circumstances, with a direct in-line substitution of a specified expression. Expression methods
are typically used for simple methods (such as those found in data type classes) that need
rapid execution speed.
For example, it is possible to convert the Speak method of the Dog class from the previous
example into an expression method:
Method Speak() As %String [CodeMode = expression]
{
"Woof, Woof"
}
Assuming dog refers to a Dog object, this method could be used as follows:
Using Caché Objects 43