anchor.diff:  the comparison implementation is container dependent, but should correspond to
   the in-memory null check.
   
  -[classname]#Equal#,[classname]#Greater#,
  - [classname]#Less#,
  - [classname]#GreaterOrEqual#, and[classname]#LessOrEqual#:: ((("[classname]#Equal# (filter)")))
  +[classname]#Equal#, [classname]#Greater#, [classname]#Less#, [classname]#GreaterOrEqual#, and [classname]#LessOrEqual#:: ((("[classname]#Equal# (filter)")))
   ((("[classname]#Greater# (filter)")))
   ((("[classname]#Less# (filter)")))
   ((("[classname]#GreaterOrEqual# (filter)")))
   ((("[classname]#LessOrEqual# (filter)")))
  -+
   The comparison filter implementations compare the specified property value to
   the given constant and pass items for which the comparison result is true. The
   comparison operators are included in the abstract [classname]#Compare# class.
  
positive.code: +
  The logical unary operator filter negates which items are passed by the filter
  given as the parameter.
  
  
  
  
  [[datamodel.container.filtered.custom]]
  === Implementing Custom Filters
  
negative.code: containers. Again for the other types of containers, the comparison is container
  dependent.
  
  [classname]#And# and [classname]#Or#:: ((("[classname]#And# (filter)")))
  ((("[classname]#Or# (filter)")))
  +
  These logical operator filters are composite filters that combine multiple other
  