4.2.  $exit

     It	is possible to change the normal flow  of  execution
by  means of the $exit built-in	routine.  The programmer may
use ($exit 0) to halt execution	of  the	 current  phase	 and
move  on  to  the next phase.  At any time, ($exit 1) may be
used to	halt the execution of the current phase	and skip  to
the  next  Actor.   Inside the Direct Object loop, ($exit 2)
may be used to skip the	rest of	the Object and Verb  ACTIONs
and  go	 on  to	 the next Direct Object	in the list.  At any
time after the parsing phase, ($exit 3)	will return the	flow
of  control  to	 the Parsing phase without clearing the	sen-
tence.	This allows for	incremental entry of sentences;	 for
example	"The big door.	Unlock.	 With the key".


     The following is a	diagram	of the flow of execution:


					   START [0]
					     |
					     v
	  +--------------------------------->o
	  |				     |
	  |				     v
	  |				  Daemons [1]
	  |				     |
	  |				     v
	  |				 Get Actor <----------------------+
	  |				     |				  |
	  |				     v				  |
	  |	  +------------------> Clear Sentence			  |
	  |	  |			     |				  |
	  |	  |			     v				  |
	  |	  |	  ($exit 3)====> Get Input? --n---> Delete Actor  |
	  |	  |			     | y		  |	  |
	  |	  |			     v			  |	  |
	  |	  o<---------------------- Parse?		  |	  |
	  |	  ^			     |			  |	  |
	  |	  |			     v			  |	  |
	  |	  o<-------------fail----- DWIMI		  |	  |
	  |	  ^			     |			  |	  |
	  |	  |			     v			  |	  |
	  |	  +--------------fail----- DWIMD		  |	  |
	  |				     |			  |	  |
	  |				     v			  |	  |
	  |				 Get Dobj <-------+	  |	  |
	  |				     |		  |	  |	  |
	  |				     v		  |	  |	  |
	  |			       Actor ACTION [2]	  |	  |	  |
	  |				Verb PREACT [3]	  |	  |	  |
	  |				Iobj ACTION [4]	  |	  |	  |
	  |				Dobj ACTION [5]	  |	  |	  |
	  |				Verb ACTION [6]	  |	  |	  |
	  |				     |		  |	  |	  |
	  |				     v		  |	  |	  |
	  |		  ($exit 2)===>	More Dobjs? -y----+	  |	  |
	  |				     | n		  |	  |
	  |				     v			  |	  |
	  |				Room ACTION [7]		  |	  |
	  |				     |			  |	  |
	  |				     v			  |	  |
	  |		  ($exit 1)=========>o<-------------------+	  |
	  |				     |				  |
	  |				     v				  |
	  +--------------------------n-	More Actors? -y-------------------+