Specification of Reactive Hardware/Software Systems - Electronic ...

6.6 Dynamic Behaviour 219
c
a
Multiple X
Figure 6.22: Common Channels on Multiple Process Objects
B is connected to the environment. Therefore it must be possible to give different outer
names to these channels.
6.6.7.2 System Specification
A specification of a whole system is defined as
Bspec¥ Sys p ¥ Sys ¡
where Bspec defines how a system is composed of collaborating instances of classes. The
behaviour description Bspec is a parameterised behaviour description which contains
no expression parameters. These classes of all clusters and processes are defined in Sys p
which is of the form:
p
CD ¡ ¡ 1 CDp ¡ k
Each CD p i is either a process class definition or a cluster class definition. Further all
non-primitive data classes are specified in Sys. Sys is of the form
CD1 ¡ ¡ CDk ¡
where each CDi is a data class definition.
The behaviour specification Bspec of a system is of one of the following forms
C p (E1 ¥¡ ¡ ¡ ¥ Er)
C c (E1 ¥¡ ¡ ¡ ¥ Er)
¢ Bspec1 Bspec2
Bspec L
Bspec§ f
C p (E1 ¥¡ ¡ ¡ ¥ Er) denotes an instance of some process class C p y1 ¥¡ ¡ ¡ ¥ yr ¡ . Upon system
initialisation, expressions E1 ¥¡ ¡ ¡ ¥ Er are evaluated from left to right and bound to the
corresponding instance variables y1¥¡ ¡ ¡ ¥ yr. All other instance variables are initialised to
nil.
C c (E1 ¥¡ ¡ ¡ ¥ Er) denotes an instance of some cluster class C c P1 ¥¡ ¡ ¡ ¥ Pr ¡ . Upon system
initialisation expression parameters P1 ¥¡ ¡ ¡ ¥ Pr are syntactically substituted by E1 ¥¡ ¡ ¡ ¥ Er.
b