(descendants tag) (descendants h tag)
Returns the immediate and indirect children of tag, through a relationship established via derive. h must be a hierarchy obtained from make-hierarchy, if not supplied defaults to the global hierarchy. Note: does not work on Java type inheritance relationships.
;; simple example a toy poodle is a poodle is a dog is an animal
user=> (derive ::dog ::animal)
nil
user=> (derive ::poodle ::dog)
nil
user=> (derive ::toy_poodle ::poodle)
nil
user=> (descendants ::animal)
#{:user/toy_poodle :user/poodle :user/dog}
user=>