example Aggregation

#Aggregation is not functorial
options
	allow_aggregation_unsafe = true

typeside Ty = literal {
	external_types
		Double -> "java.lang.Double"
	external_parsers
		Double -> "x => java.lang.Double.parseDouble(x)"
	external_functions
		plus : Double,Double -> Double = "(x, y) => 0.0 + x + y"
}

schema S = literal : Ty {
	entities
		Emp Dept
	foreign_keys
		worksIn : Emp -> Dept
	attributes
		salary : Emp -> Double
}

schema T = literal : Ty {
	entities
		Dept
	attributes
		totalCost : Dept -> Double
}

instance I = literal : S {
	generators
		p1 p2 p3 p4 : Emp
		d1 d2 : Dept
	equations
		p1.salary = "10" #p2.salary = "1"
		p1.worksIn = d1 p2.worksIn = d1

		p3.salary = "50" #p2.salary = "1"
		p3.worksIn = d2 p4.worksIn = d2

}

query Q1 = literal : S -> T {
	entity Dept -> {from d:Dept
  			attributes totalCost -> from p:Emp
				where worksIn(p) = d
  	    		return salary(p)
  	    		aggregate 0 lambda arg1 arg2. plus(arg1,arg2)
	}
}

instance J = eval Q1 I

instance I

instance J