&trace := 2 ----> 2
std85.icn: 10	| dummy(1,&null,&null,&null,&null)
std85.icn: 4	| dummy suspended 1
dummy(1) ----> 1
1
2.0
&null
every write(image(dummy(1,2.0,&null,[]))) ----> none
&trace ----> 0
&trace := -1 ----> -1
std85.icn: 14	| dummy(1,2.0,&null,[],&null)
std85.icn: 4	| dummy suspended 1
1
std85.icn: 14	| dummy resumed
std85.icn: 4	| dummy suspended 2.0
2.0
std85.icn: 14	| dummy resumed
std85.icn: 5	| dummy returned &null
&null
every write(image(dummy(1,2.0,&null,[]))) ----> none
&trace ----> -1
std85.icn: 16	| dummy(&null,&null,&null,&null,&null)
std85.icn: 4	| dummy suspended &null
dummy() ----> &null
std85.icn: 17	main failed