This chapter describes two kinds of custom data structures
that you can define in LotusScript®.
Each can hold data of different types in a single data structure.
Overview of user-defined data types and classes
User-defined classes are common to object-oriented programming and are used to represent objects whose data can be protected, initialized, and accessed by a specific set of procedures.
User-defined data types
User-defined data types are a common feature in BASIC programming
and are used to support database, file read/write, and print operations.
A user-defined data type lets you group data of different types in
a single variable. This data type can contain any kind of related
information you want to store and use together, such as personnel
information, company financial information, inventory, and customer
and sales records. A variable of a user-defined data type holds actual
data, not a pointer to that data.
User-defined classes
You can build object-oriented applications by creating
classes. A class is a data type that restricts access to its data
to a set of procedures. These procedures control the ways that an
instance of a class (an object) is initialized, accessed, and finally
deleted when it is no longer needed.
Derived Classes
A derived class is created from a previously defined class.
Arrays and lists of classes
If you're working with groups of objects, you can create an array or list that includes the objects as elements.
Working with object reference variables
You use an object reference variable to create, manage,
and delete objects. It has the data type of a class and, like other
variables, is a named area in storage. However, unlike other variables,
the value stored in the area is not the object itself but a 4-byte
pointer to the object data, called an object reference. LotusScript uses this pointer to access
the object data.