&trace := -1 ----> -1
xpx01.icn: 10	| dummy([co-expression,co-expression,co-expression,co-expression],&null,&null,&null,&null)
xpx01.icn: 4	| dummy suspended [co-expression,co-expression,co-expression,co-expression]
list(4)
xpx01.icn: 10	| dummy resumed
xpx01.icn: 4	| dummy suspended &null
&null
xpx01.icn: 10	| dummy resumed
xpx01.icn: 5	| dummy returned &null
&null
every write(image(dummy{1,2,3,4})) ----> none
xpx01.icn: 11	| dummy([],&null,&null,&null,&null)
xpx01.icn: 4	| dummy suspended []
list(0)
xpx01.icn: 11	| dummy resumed
xpx01.icn: 4	| dummy suspended &null
&null
xpx01.icn: 11	| dummy resumed
xpx01.icn: 5	| dummy returned &null
&null
every write(image(dummy{})) ----> none
image{1,2,3,4} ----> "list(4)"
image(put{1,2,3,4}) ----> "list(5)"
"*"{1,2,3,4} ----> 4
image("|||"([],[])) ----> "list(0)"
"+"(1,2) ----> 3
"+"(1) ----> 1
function write
"write"(image(write)) ----> "function write"
Run-time error 106 at line 19 in xpx01.icn
procedure or integer expected
offending value: "x"