SIMSCRIPT II.5 Programming Language

Discrete Simulation Concepts
To use before or after tracing, routines having the same number of input arguments as are transmitted
for the operation being monitored are written and included with the program. These arguments
will be used to pass entity pointers or index values, and any required subscripts, to the usersupplied
checking routines.
Suppose, for example, during the validation of a simulation model, it is desired to display the simulation
times at which any SHIP entities are filed in a BERTH.SET. The statements to do this might
be:
Preamble:
Routine:
permanent entities
every HARBOR may own a BERTH.SET
.
.
temporary entities
every SHIP has a TONNAGE
and may belong to a BERTH.SET
.
.
before filing in BERTH.SET call CHECK
.
.
routine CHECK given SHIP, SUB1
define SHIP and SUB1 as integer variables
list time.v, attributes of SHIP, SUB1
return
end
As shown, the routine must be written to accept the correct number of set subscripts. BERTH.SET,
here, is one-dimensional and the dimension identifies the owning HARBOR. As in the case of monitored
variables, these calls may be added to or removed from a program, with minimal effort, and
require no modification to any existing program routines.
Table 5-10 lists the variations of the before and after statements, with the arguments passed to
the routines called.
235