How to have arbitrary observational equations involving java types

Hi, I have a requirement where I need observation_equations involving java types. How can I possibly do that?

typeside Ty = literal {
    external_types
        Int -> "java.lang.Integer"

    external_parsers
        Int -> "parseInt"

    external_functions
        min : Int, Int -> Int = "(x, y) => x < y ? x : y"
}

schema C = literal : Ty {
    entity
        A

    foreign_keys

    path_equations

    attributes
        x : A -> Int
        y : A -> Int

    observation_equations
        forall a. a.x = min(a.x, a.y) # I just want to check a.x < a.y. How can I do that?
}

So in this simplified example, I want to enforce that all instances of schema C should fulfil the constraint that forall a. a.x < a.y. Is there a way to implement this?

CategoricalData / CQL

How to have arbitrary observational equations involving java types #71