Castable

A type for all objects belonging to a hierarchy rooted in T which can be down-casted to any subtype of T via explicit methods, rather than via Kotlin's as/as? operators.

This is useful for hierarchies (e.g. it.unibo.tuprolog.core.Term in the :core module) exposing many mutually exclusive subtypes, where call sites need a concise, fluent way to narrow a value down after a type check (e.g. term.castToInteger()), without repeating verbose as Integer casts everywhere. Callers that want a null instead of an exception on a failed cast should use as rather than castTo:

sealed interface Term : ... , Castable<Term> {
    fun castToInteger(): Integer = castTo()
}

Type Parameters