Core.Declarations.GlobalDeclarations

Classification

Name	Global Declarations
Short Description	Global variables and constants
Class	OTX Core
Pre-Conditions	-
Specified by	ISO 13209-2

Introduction

The following elments can be declared in the global declaration block:

• Global Constants
• Context Variables
• State Variables
• Document Variables

These elements have a global scope. That is, they can be used anywhere within the document in which they are declared, as well as in other documents, see Imports. One global declaration of a document can not have the same with another global declaration of the same document.

Semantics

Global Constant

The value of a global constant is set at design-time and can not be changed at runtime. The global constants must have one of the following Visibilities:

• Private (default)
• Package
• Public

A constant has a Type and it must have a initial value corresponding to the type. As a result, they can not has Type which does not has an explicit value.

Context Variable

Context variables are environment variables which behave like global constants. However, they have a special meaning. They represent environment-related data, such as vehicle type, name of workshop, user login name, etc., see the Context Concept. Context variables are the counter part of state variables. They are mechanism to transport environment information to the sequence. The context variables must have one of the following Visibilities:

• Private (default)
• Package
• Public

A context variable has a Type and it may have an initial value corresponding to the type.

State Variable

State variables are environment variables which behave like global variables. However, state variables can only be set and cannot read inside OTX, the test logic shall not be based on the value of a State variable. State variables are the counter part of context variables. They are mechanism to transport status information from inside a sequence to the environment. The state variables must have one of the following Visibilities:

• Private (default)
• Package
• Public

A state variable has a Type and it may have a initial value corresponding to the type.

Global Variable (Document Variable)

The value of a global variable can be changed at runtime. Global variables can only be used in the same document. Therefore, they only have one following Visibility:

• Private (fixed)

A variable has a Type and it may have a initial value corresponding to the type.

Checker rules

Core_Chk009	Mandatory constant initialisation
Core_Chk051	Immutability of constants, input parameters and context variables
Core_Chk052	Identifier shadowing
StatVar_Chk001	State variables shall not read

See also

Validation (OTX-Checker)
​​Naming Conventions
Imports
Visibilities
Validities
Signatures
Parameter Declarations
Procedures
Comments