We assume that you grasped the first steps of opening and animating a B machine as outlined in Tutorial First Steps.
In this lesson, we examine more closely the various steps that ProB undertakes before a machine can be animated.
First, open the machine "Jukebox.mch" which can be found in the SchneiderBook/Jukebox_Chapter13 subdirectory of the ProB Examples folder. The main ProB window should look more or less as follows:
In general, before the operations of a machine can be applied, ProB needs to traverse three phases:
This process is illustrated in the following picture:
We now examine these phases on the Jukebox machine in more detail
Here ProB parses and type checks the machine.
Then it will fix the values of MININT and MAXINT. There are two ways you can influence this:
Note that these preferences determine the elements of the sets INT (implementable integers), NAT (implementable natural numbers) and NAT1. In addition, they are used to control the enumeration of variables of type INTEGER</tt) (mathematical integers), in case a definite value cannot be inferred from the machine.
Afterwards, ProB will determine the cardinality of all deferred sets (such as TRACK in the Jukebox machine).There are several ways you can influence this:
As you can see above, ProB has chosen MAXINT=3, MININT=-1 and card(TRACK)=2.