VDM-10 Language Manual

VDM-10 Language Manual
CPU1.deploy(a);
-- deploy b on CPU1
CPU1.deploy(b);
-- deploy c on CPU2
CPU2.deploy(c,"CT");
-- "CT" is a label here which is ignored
);
end Simple
✡✝
✆
where A, B and C all are defined as classes.
14.2 Classes
Compared to the standard VDM-SL language, VDM++ and VDM-RT have been extended with
classes. In this section, the use of classes to create and structure a top-level specification will be
described. With the object oriented facilities offered by VDM++ and VDM-RT it is possible to:
• Define classes and create objects.
• Define associations and create links between objects.
• Make generalisation and specialisation through inheritance.
• Describe the functional behaviour of the objects using functions and operations.
• Describe the dynamic behaviour of the system through threads and synchronisation constraints.
Before the actual facilities are described, the general layout of a class is described.
Syntax: class = ‘class’, identifier, [ inheritance clause ],
[ class body ],
‘end’, identifier ;
inheritance clause = ‘is subclass of’, identifier, ‘,’, { identifier } ;
class body = definition block, { definition block } ;
definition block = type definitions
| value definitions
| function definitions
| operation definitions
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