package prolog.components.terms

import prolog.components.Program
import prolog.components.Provable

/**
 * Ask the Prolog engine.
 *
 * A goal is either an [Atom] or a [CompoundTerm].
 * A goal either [succeeds][prolog.builtins.True], in which case the variables in the compound terms have a binding,
 * or it fails if Prolog fails to prove it.
 */
abstract class Goal : Term, Provable {
    abstract val functor: Functor

    override fun prove(): Boolean = Program.query(this)
}