test3.dlq

;test.people.filter{$father}(
;  $father.gender.eq('male')
;  $father.age.gte(32)
;  $father.children.filter{$child}(
;    test.people.filter{$mother}(
;      $mother.languages.contains('SE')
;      $mother.gender.eq('female')
;      $mother.children.contains($child)
;    )
;  )
;)
;{
;  $father [*]
;  $child [name]
;}
;
;
; JS mockup of above (without clear projection)
;test.people.filter(function($father) {
;  return $father.gender === 'male' &&
;  $father.age >= 32 &&
;  $father.children.filter(function($child) {
;    return test.people.filter(function($mother) {
;      ~return $mother.languages.indexOf('SE') &&
;      $mother.gender === 'female' &&
;      ~$mother.children.indexOf($child);
;    });
;  });
;}).project(function($parent) {
;  return $parent;
;});


;;test.people{father}.filter(
;;  father.gender.eq('male')
;;  father.age.gte(32)
;;  father.children{test.people child idx}.filter(
;;    idx.mod(2)
;;    test.people{mother}.filter(
;;      mother.languages.contains('swedish')
;;      mother.gender.eq('female')
;;      mother.children{test.people}.contains(child)
;;    )
;;  )
;;)

;;defn(
;;  join-child(child idx)
;;  test.people{p}.$filter(
;;    child.$eq(p.name)
;;  )
;;)
;;
;;test.people{father}.$filter(
;;  father.gender.$eq('male')
;;  father.children.$map(join-child){child}.$filter(
;;    child.age.$gte(18)
;;    test.people{mother}.$filter(
;;      mother.$neq(father)
;;      mother.children.$contains(child.name)
;;    )
;;  )
;;)
;;
;;test.people{person}.$filter(
;;  person.gender.$eq('male')
;;){male}.filter(
;;  male.children.$map(join-child){child}.$filter(
;;    child.age.$gte(18)
;;    test.people{person2}.$filter(
;;      person2.$neq(male)
;;      person2.children.$contains(child.name)
;;    )
;;  )
;;)


;; you have a collection of people, and you're looking for the children of all father older than 30 and all mothers who speak swedish

;; simple case: get all people who are children

;;test.people{person}.$filter(
;;  person.children{child}
;;){parent}.$map(parent.children).$concat
;;
;;;; or simpler
;;
;;test.people{person}.$map(person.children).$concat
;;
;;;; which only returns the names or ids (foreign keys), so to get the children as documents....
;;
;;test.people{person}.$map(
;;  person.children{child}.$map(
;;    test.people{p}.$filter(child.$eq(p.name))
;;  ).$concat
;;).$concat
;;
;;
;;test.people{person}.$map(
;;  person.children{child test.people{p}.$filter(
;;).$concat

;;test.people{person}.$filter(
;;  person.children
;;){parent}.$map(parent.children)
;;
;;$map(
;;  $filter(
;;    people(test){person}
;;    children(person)
;;  ){parent}
;;  children(parent)
;;)
;;
;;(map
;;  (filter
;;    (people test)
;;    (fn [person] children(person)))
;;  (fn [parent] (children parent)))

$map(
  $filter(
    people(test)
    fn([person] children(person))
  )
  fn([parent] children(parent))
)

test.people.$filter(
  fn([person] person.children)
).$map(
  fn([parent] parent.children)
).$cat