For this tutorial, load for example the file StackConstructive.mch included in the examples/Tutorial directory of the ProB distribution.
After loading the file, double click on the green line "SETUP_CONSTANTS" in the "Enabled Operations" pane. Now double click on the green "INITIALISATION" line in the same pane. To start the "Eval..." interactive console you can either
This will bring up a new window, the "Eval Console":
You can now enter predicates or expressions and hit return or enter to evaluate them in the current state of the machine. Below is a small transcript:
You can use the up and down arrow keys to navigate to earlier predicates or expressions you have entered.
If you change the state, then the expressions and predicates are evaluated in that state. For example, if you execute the operations Push(RANGE3), Push(RANGE1), Push(RANGE2), then a transcript of using the console is as follows: