step 11 + 8 = 19 4.3.7.11 Declaring simulation variables Simulation variables can be declared in the Simulator: work variables: using the command dcl, like in SDL environment variables: using the command define Example of work variable: dcl X integer let X = 45 print X let = X + 1 Interactive Simulation 105 Example of environment variable (extract from the script in Section 4.3.6): define test failed False if $test_failed; echo 'TEST FAILED' else; echo 'TEST PASSED'; fi 4.3.7.12 Two important Simulator options The Simulator behavior can be configured thanks to several options; to see all the options, enter the textual command define. For the main options, the Edit > Configuration command opens the Simulator configuration window represented in Figure 4.64. Configuration Random number seed: 619430284 Apply Options Scenario recording Reasonable environment define reasonabl feed false Loose time progression define loose_time 'true' Trap outputs without receiver Trap outputs to process with more than one instance Trap unexpected signals Sort fireable transitions alphabetically Check Range Conditions in let commands Close Figure 4.64 The Simulator configuration window We explain two important options here: reasonable environment and loose time progression. If you want to set these options automatically, enter the appropriate define command, indi- cated in Figure 4.64, in one of your Simulator startup files. Reasonable environment allows the input of an external signal (coming from the feed com- mand) only if the SDL model is in a 'quiet' state. Quiet means that all the input queues in the SDL model are empty and all the start transitions have been executed. For example, if you start the simulation of V.76 and click on init K after starting process dispatch you get nine firable transitions with reasonable environment off, instead of three transitions if you turn it on, as illustrated in Figure 4.65. When on, the Simulator wants you to first finish starting all the process instances before enabling the input of external 