= statement

The = statement creates a new property.

Syntax

name [caption] [(param1, ..., paramN)] = expression [options];
name [caption] [(param1, ..., paramN)] = contextIndependentOperator [options];

name [caption] [(param1, ..., paramN)] = NATIVE returnClass (argClass1, ..., argClassM) [options];

Description

The = statement declares a new property and adds it to the current module.

When creating a property, the statement has two main forms:

• The first form describes and creates a property using an expression.
• The second form describes the property using one of the context-independent property operators that cannot be part of an expression.

The third form with the keyword NATIVE is used in some system modules. It is used to declare individual system properties that are created before the modules are initialized.

When declaring a property, its set of options can also be specified.

Parameters

• name

  The name of the property. Simple ID.

• caption

  Property caption. String literal. If no caption is specified, then the property caption will be its name.

• param1, ..., paramN

  List of parameters. Each of these is specified by a typed parameter. These parameters can then be used in the expression describing the property being created (as well as in some options).

  If parameters are not specified explicitly, they will be automatically calculated when processing the expression. The order of the parameters will correspond to the order in which the parameters appear in the expression. It is recommended that you explicitly specify property parameters. This will allow to find typos and other errors in the declaration (for example, a mismatch of the number of parameters provided with the number of parameters of the created property).

• expression

  An expression that describes and creates a property.

• contextIndependentOperator

  A context-independent property operator that describes and creates a property.

• options

  Property options.

• returnClass

  Class ID of the property's return value.

• argClass1, ..., argClassM

  List of class IDs for the property's arguments.

Examples

// property defined by the context-independent DATA property operator
cost 'Cost' (i) = DATA NUMERIC[12,3] (Item);

// property defined by expression
weightedSum 'Weighted amount' (a, b) = 2*a + 3*b;

// the caption of this property will be 'diff' and the parameters will be (a, b)
diff = a - b;

// property defined by DATA operator with additional property options
teamName 'Team name' = DATA BPSTRING[30](Team) IN baseGroup TABLE team;