commonMain.it.unibo.tuprolog.solve.function.ExpressionEvaluator.kt Maven / Gradle / Ivy

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package it.unibo.tuprolog.solve.function

import it.unibo.tuprolog.core.Struct
import it.unibo.tuprolog.core.Term
import it.unibo.tuprolog.solve.ExecutionContext
import it.unibo.tuprolog.solve.exception.error.TypeError
import it.unibo.tuprolog.solve.primitive.Solve

/**
 * Evaluates a [Term] as an expression, w.r.t. the loaded functions provided through [request].
 * Throws a [TypeError] in case a non-evaluable sub-term is met.
 *
 * @param request the request of the primitive in which the evaluation should happen
 * @param index the index of the argument being evalued in the aforementioned primitive
 */
class ExpressionEvaluator(
    request: Solve.Request,
    index: Int? = null
) : AbstractEvaluator(request, index) {

    override fun unevaluable(struct: Struct): Term =
        throw TypeError.forArgument(request.context, request.signature, TypeError.Expected.EVALUABLE, struct, index)
}