procedure main()
   write(image(t := table()) | "failed")
   write(image(every i := 1 to 20 do t[i] := i) | "failed")
   write(image(?t) | "failed")
   write(image(?t) | "failed")
   write(image(?t) | "failed")
   write(image(?t) | "failed")
   write(image(?t) | "failed")
   write(image(?t) | "failed")
   write(image(?t) | "failed")
   write(image(?t) | "failed")
   write(image(?t) | "failed")
   write(image(?t) | "failed")
   write(image(t := table()) | "failed")
   write(image(every t[c := !(12345678 || &lcase)] := c) | "failed")
   write(image(every write(!t)) | "failed")
   write(image(set([1,0,1,0,1,0,1,0])) | "failed")
   write(image(set([])) | "failed")
   write(image(s := set([1,2,3,4,5,6,7,8,9,10])) | "failed")
   write(image(?s) | "failed")
   write(image(?s) | "failed")
   write(image(every write(!s)) | "failed")
   write(image(s := set([])) | "failed")
   write(image(every insert(s,1 to 20)) | "failed")
   write(image(every write(!s)) | "failed")
   write(image(every delete(s,15 to 30)) | "failed")
   write(image(every write(!s)) | "failed")
   write(image(every s1 := insert(set([]),!&lcase)) | "failed")
   write(image(s2 := set(["a","aa","ab","b",1,2,3,4])) | "failed")
   write(image(s3 := s1 ++ s2) | "failed")
   write(image(s4 := s1 ** s2) | "failed")
   write(image(s5 := s1 -- s2) | "failed")
   write(image(*s3) | "failed")
   write(image(every write(!s3)) | "failed")
   write(image(*s4) | "failed")
   write(image(every write(!s4)) | "failed")
   write(image(every write(!s5)) | "failed")
end