Methods

Methods are implemented as regular defined functions, but with some special attributes that control how they are called and where they are executed.

A Method is defined by a contiguous block of statements in a Class Script. A Method begins with a line that contains a ∇, followed by a valid APL defined function header. The method definition is terminated by a closing ∇.

Public or Private

Methods may be defined to be Private (the default) or Public.

A Private method may only be invoked by another function that is running inside the Class namespace or inside an Instance namespace. The name of a Private method is not visible from outside the Class or an Instance of the Class.

A Public method may be called from outside the Class or an Instance of the Class.

Instance or Shared

Methods may be defined to be Instance (the default) or Shared.

An Instance method runs in the Instance namespace and may only be called via the instance itself. An Instance method has direct access to Fields and Properties, both Private and Public, in the Instance in which it runs.

A Shared method runs in the Class namespace and may be called via an Instance or via the Class. However, a Shared method that is called via an Instance does not have direct access to the Fields and Properties of that Instance.

Shared methods are typically used to manipulate Shared Properties and Fields or to provide general services for all Instances that are not Instance specific.

Overridable Methods

Instance Methods may be declared with :Access Overridable.

A Method declared as being Overridable is replaced in situ (i.e. within its own Class) by a Method of the same name that is defined in a higher Class which itself is declared with the Override keyword. See Superseding Base Class Methods.