commonMain.it.unibo.tuprolog.solve.stdlib.primitive.NumberChars.kt Maven / Gradle / Ivy

Go to download
package it.unibo.tuprolog.solve.stdlib.primitive

import it.unibo.tuprolog.core.Atom
import it.unibo.tuprolog.core.Numeric
import it.unibo.tuprolog.core.Substitution
import it.unibo.tuprolog.core.Term
import it.unibo.tuprolog.core.Var
import it.unibo.tuprolog.core.toAtom
import it.unibo.tuprolog.solve.ExecutionContext
import it.unibo.tuprolog.solve.primitive.BinaryRelation
import it.unibo.tuprolog.solve.primitive.Solve
import it.unibo.tuprolog.core.List as LogicList

object NumberChars : BinaryRelation.Functional("number_chars") {
    override fun Solve.Request.computeOneSubstitution(
        first: Term,
        second: Term,
    ): Substitution {
        return when {
            first is Var && second is Var -> {
                ensuringAllArgumentsAreInstantiated()
                Substitution.failed()
            }

            first is Var -> {
                ensuringArgumentIsList(1)
                val chars = second as LogicList
                val numberString = chars.toSequence().map { (it as Atom).value[0] }.joinToString("").trim()
                Substitution.of(first, Numeric.of(numberString))
            }
            second is Var -> {
                ensuringArgumentIsNumeric(0)
                val number = (first).toString().toAtom().value
                val chars = LogicList.of(number.map { Atom.of("" + it) })
                Substitution.of(second, chars)
            }
            else -> {
                ensuringArgumentIsNumeric(0)
                ensuringArgumentIsList(1)
                val chars =
                    LogicList.of(
                        (first).toString().toAtom().value.map { Atom.of("" + it) },
                    )
                mgu(chars, second)
            }
        }
    }
}