This example displays the current state of a finite state machine
model execution.
First, the USE clause makes the contents of the TEXTIO package
available. The enumerated type STATE is also declared. The procedure
display_state requires only one input value, the current state
of the FSM.
Several local variables are declared. The buffer k of type
LINE will be used for WRITE storage. The FILE flush is of type
text and will output to a file named /dev/tty. This logical
name is the standard output or screen in UNIX. Therefore, the
procedure will write to the screen. The variable state_string
holds the text value of the state.
The CASE statement converts the state of the FSM into a text value.
The WRITE statement then writes the value of state_string to the
buffer k. The WRITE statement further specifies that the string
should be left justified and be 7 spaces wide.
Finally, the WRITELINE sends the buffer k to the file
flush. The text is then written to the screen.
Note that this procedure would not work very well for writing to a
file. Since the file is re-initialized every time the procedure is
used, the text would always be written to the beginning of the file.
Using TEXTIO to write to a file requires that the file be passed to the
procedure as a parameter, or the modeler could use a process that
implements the same functionality.
Based on [Navabi93]
