Description of operation

  
   add_set_op
  | append_op 
  | case_op
  | copy_op
  | insert_op
  | intersect_op
  | keep_op
  | merge_op
  | minus_op  
  | nested_path_op
  | prepend_op
  | remove_op
  | remove_set_op
  | rename_op
  | replace_op   
  | set_op  
  | sort_op
  | union_op