Add Local Properties at Runtime


STATIC [ varlist | * ]



List of variables for use within an object or an * (asterisk) to enable full variable persistence.


In Object Oriented Programming (OOP), the STATIC directive is used to create variables for use within an object at run time that will be preserved within the object instance. STATIC is used to extend the list of LOCAL properties at run time. This allows for the dynamic creation of variables which are visible to operations within an object, yet which are not directly accessible to outside code.

Specifying an * (asterisk) indicates all variables are to be considered LOCAL and is referred to as Full Variable Persistence.


static A$,B,iol=iol(1)

All the named variables will be LOCAL so that their values will remain current while executing logic within the object.

Using the STATIC clause, an object that is accessing a data file with an embedded IOList will be able to handle extensions to the IOList going forward. This allows the object to then read a record from the file and have the data elements remain available for subsequent calls to the object's methods.

Duplicate variables are ignored; i.e. if a variable has already been declared STATIC, is a PROPERTY, or has been declared LOCAL for an object, then no error is reported. Static variables will include their associated arrays; therefore, STATIC A$ also means that A$[1],... are all static.

Ensure that the STATIC declaration occurs before the variables are used. Static variables will only take effect on references that follow their declaration.

Full Variable Persistence

The STATIC * directive indicates that all variables used within an object are to be preserved within the object. This means that any variable value set during the execution of the object will remain set on subsequent method/function calls.

The directive can be placed either within the class definition or executed at any time during the execution of the object. Once full variable persistence is enabled within an object, it cannot be disabled.

Full variable persistence is not honoured for functions/methods within an object that are declared as "performed". This is due to the fact that performed functions share the variable space with the calling logic.

See Also

DEF CLASS Define Object Class
DROP CLASS Delete Class Definition
DROP OBJECT Delete Object
FUNCTION Declare Object Method
LIKE Inherit Properties
LOAD CLASS Pre-Load Class Definition
LOCAL Designation of Local Data
PROGRAM Create/Assign Program File
PROPERTY Declare Object Properties
RENAME CLASS Change Name of Class
NEW( ) Create New Object
REF( ) Control Reference Count