The previous example uses two modules, M1
and M2
, one representing each process.
A module is specified as:
The definition of a module contains two parts: its variables and its guards.
In this example, each module has one integer variable with range [0..2]
.
A variable declaration looks like:
Notice that the initial value of the variable is also specified. See the next subsection for more information about this subject. Boolean variables can also be used, e.g.:
The names given to modules and variables are referred to as identifiers.
Identifiers can be made up of letters, digits and the underscore character, but cannot begin with a digit,
i.e. they must satisfy the regular expression [A-Za-z_][A-Za-z0-9_]*, and are case-sensitive.
Furthermore, identifiers cannot be any of the following, which are all reserved keywords in PRISM:
A
, bool
, const
, ctmc
, C
, double
, dtmc
, E
, endinit
, endmodule
, endrewards
, endsystem
, false
, formula
, func
, F
, global
, G
, init
, I
, int
, label
, max
, mdp
, min
, module
, X
, nondeterministic
, Pmax
, Pmin
, P
, probabilistic
, prob
, rate
, rewards
, Rmax
, Rmin
, R
, S
, stochastic
, system
, true
, U
, W
,