Scripting Objects

Scripts can interact with Opus using a number of different objects. For example, the Lister object represents a physical window, providing information about that Lister to the script and letting the script modify or control that Lister.

An object has two main types of interface that you can call on:

Properties let the script query (and sometimes set) a simple value. For example, the Lister object has a title property that lets the script retrieve the Lister window's title string.
Methods are functions an object provides that the script can invoke to perform a task. For example, the DOpus object has an Output method that lets the script output a text string to the script log.

The main distinction between properties and methods is that methods can (but don't always) accept arguments that modify their behavior, and don't have to (but often do) return a result.

Variable types

Properties and methods that return a result can return a number of different types of variables, and methods often take one or more parameters that can also be a number of types. ActiveX scripting languages are generally typeless - that is, a variable's type does not have to be defined in advance, and conversion from one type to another is often (but not always) automatic. Opus scripting mainly uses variables of the following types:

Int - a whole number (signed; valid range is -2147483648 to 2147483647).
Currency - this is a standard variant type, and is used by Opus in just a couple of cases that require numbers larger than an Int can hold (unfortunately ActiveX scripting does not always support a 64 bit integer type).
Decimal - an unsigned 64 bit value (maximum value 18,446,744,073,709,551,616). Not all languages support this - JScript does, but VBScript does not.
String - a text string
Bool - a Boolean (either True or False)
Date - a date/time value
Collection - a collection of multiple objects of (generally) the same type. Collections can be easy enumerated in some languages (e.g. in VBScript, using the For Each construct). Collections are only returned by Opus - unlike an array (or a Vector object), they are never created or modified directly (although some script methods can be used to modify them in certain cases). For example, the Tab object has a property called selected that represents all currently selected items in that tab - it is a collection of items.
Object - an Opus script object with defined methods and properties (one of the object types listed below). Some objects can be both an object and a collection - that is, they have methods and properties, but can also be enumerated like a collection. Some objects also have a default value - that is, simply using the object's name without any method or property will return a value of its own. For example, the Metadata object's default value is a string indicating the primary type of metadata available. You can also refer to an object's default value using the special def_value property name.
Variant - a variable of any type (this is used with a few objects - for example, a Var object can store a variant)

Global objects

There are two objects that are provided to scripts as global variables when they are invoked by Opus:

Event objects

Other objects

The remaining objects are all obtained using methods or properties provided by the objects listed above. For example, a Lister object is obtained using the DOpus.listers collection property, and a Vector object is obtained using the DOpusFactory.Vector method.

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