00100	(ADD(IF-NEEDED PRE-AND(FOO)
00200	"AUX"((CS CONTEXT) (C1(PUSH-CONTEXT)) C2 Z1 Z2 Z3)
00300	(CSETQ CONTEXT C1)
00400	(CSETQ Z1(FETCH '(PRE1)))
00500	:L (TRY-NEXT Z1 '(GO 'NA))
00600	(CSETQ C2(PUSH-CONTEXT))
00650	(CSETQ CONTEXT C2)
00700	(CSETQ Z2(FETCH '(PRE2)))
00800	:M(TRY-NEXT Z2 '(GO 'LA))
00900	(CSETQ Z3 (FETCH '(PRE3)))
01000	(TRY-NEXT Z3 '(GO 'MA))
01100	(ADD '(POS1))
01150	
01200	(ADIEU)
01300	:LA(PRINT 'BACKING)(CSETQ CONTEXT CS)(CSETQ C1(PUSH-CONTEXT))(GO 'L)
01400	
01500	:MA(CSETQ CONTEXT C1)(CSETQ C2(PUSH-CONTEXT))(GO 'M)
01600	
01650	:NA(CSETQ CONTEXT CS)
01675	(ADIEU 'LOSE)
01700	))
01800	(ADD(IF-NEEDED PR1A(PRE1)(ADD '(PR1))(ADD '(A))(ADIEU 'OK )))
01900	(ADD(IF-NEEDED PR1B(PRE1)(ADD '(PR1))(ADD '(B))(ADIEU 'OK)))
01950	(ADD (IF-NEEDED XX(PRE2)(COND((PRESENT '(B))(ADIEU))(T(ADIEU 'OK)))))
01975	(ADD '(PRE3))
02000	(CSETQ ZZ(FETCH '(FOO)))(TRY-NEXT ZZ)