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Resolution-agnostic API for logic solvers

There is a newer version: 1.0.4

package it.unibo.tuprolog.solve.stdlib.primitive

import it.unibo.tuprolog.core.Rule
import it.unibo.tuprolog.core.Substitution
import it.unibo.tuprolog.core.Term
import it.unibo.tuprolog.solve.ExecutionContext
import it.unibo.tuprolog.solve.exception.error.PermissionError
import it.unibo.tuprolog.solve.exception.error.PermissionError.Operation.ACCESS
import it.unibo.tuprolog.solve.exception.error.PermissionError.Permission.PRIVATE_PROCEDURE
import it.unibo.tuprolog.solve.extractSignature
import it.unibo.tuprolog.solve.primitive.BinaryRelation
import it.unibo.tuprolog.solve.primitive.Solve
import it.unibo.tuprolog.utils.buffered

object Clause : BinaryRelation.WithoutSideEffects("clause") {
    override fun Solve.Request.computeAllSubstitutions(
        first: Term,
        second: Term,
    ): Sequence {
        ensuringArgumentIsInstantiated(0)
        ensuringArgumentIsStruct(0)
        if (!second.isVar) {
            ensuringArgumentIsCallable(1)
        }
        val head = first.castToStruct()
        val headSignature = head.extractSignature()
        if (context.libraries.hasProtected(headSignature)) {
            throw PermissionError.of(context, signature, ACCESS, PRIVATE_PROCEDURE, headSignature.toIndicator())
        }
        val template = Rule.of(head, second)
        return (context.staticKb[head] + context.dynamicKb[head].buffered()).map {
            mgu(it, template)
        }.filter {
            it.isSuccess
        }
    }
}