package queries
 
import "http://www.example.org/familytree"

@Constraint(message="memberIsItsOwnParent", severity="error", key={m})
pattern memberIsItsOwnParent(m: Member) = {
	FamilyTree.members(_, m);
	Member.parents(m, p);
	m == p;
}

@Constraint(message="twoMembersHaveNoParent", severity="error", key={m1, m2})
pattern twoMembersHaveNoParent(m1:Member, m2:Member) = {
	neg find memberHasParent(m1);
	neg find memberHasParent(m2);
	m1 != m2;
}

pattern memberHasParent(m: Member) = {
	Member.parents(m, _);
}

@Constraint(message="parentTooYoung", severity="error", key={m, p})
pattern parentTooYoung(m: Member, p: Member) = {
	FamilyTree.members(_, m);
	Member.parents(m, p);
	Member.age(m, mAge);
	Member.age(p, pAge);
	check (mAge <= (pAge + 12));
}