commonMain.it.unibo.tuprolog.solve.rule.RuleWrapper.kt Maven / Gradle / Ivy

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Resolution-agnostic API for logic solvers

There is a newer version: 1.0.4

package it.unibo.tuprolog.solve.rule

import it.unibo.tuprolog.core.Rule
import it.unibo.tuprolog.core.Scope
import it.unibo.tuprolog.core.Struct
import it.unibo.tuprolog.core.Term
import it.unibo.tuprolog.core.VariablesProvider
import it.unibo.tuprolog.solve.AbstractWrapper
import it.unibo.tuprolog.solve.ExecutionContext
import it.unibo.tuprolog.solve.Signature
import kotlin.collections.List as KtList

// TODO: 16/01/2020 document and test this class
abstract class RuleWrapper(signature: Signature) : AbstractWrapper(signature) {
    constructor(functor: String, arity: Int, vararg: Boolean = false) :
        this(Signature(functor, arity, vararg))

    private val scope: Scope = Scope.empty()

    protected val variables = VariablesProvider.of(scope)

    final override val implementation: Rule by lazy {
        val headArgs = scope.head
        require(headArgs.size == signature.arity)
        val body = scope.body
        Rule.of(Struct.of(functor, headArgs), body)
    }

    open val Scope.head: KtList get() = emptyList()

    open val Scope.body: Term get() = truthOf(true)

    final override fun toString(): String {
        return "RuleWrapper(signature=${signature.toIndicator()}, rule=$implementation)"
    }
}