commonMain.it.unibo.tuprolog.solve.stdlib.function.FloatingPointDivision.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.stdlib.function

import it.unibo.tuprolog.core.Integer
import it.unibo.tuprolog.core.Numeric
import it.unibo.tuprolog.core.Real
import it.unibo.tuprolog.solve.ExecutionContext
import it.unibo.tuprolog.solve.function.BinaryMathFunction
import org.gciatto.kt.math.BigDecimal
import org.gciatto.kt.math.MathContext

/**
 * Implementation of `'/'/2` arithmetic functor
 *
 * @author Enrico
 */
object FloatingPointDivision : BinaryMathFunction("/") {
    override fun mathFunction(
        integer1: Integer,
        integer2: Integer,
        context: ExecutionContext,
    ): Numeric = commonBehaviour(integer1.decimalValue, integer2.decimalValue, context)

    override fun mathFunction(
        real: Real,
        integer: Integer,
        context: ExecutionContext,
    ): Numeric = commonBehaviour(real.value, integer.decimalValue, context)

    override fun mathFunction(
        integer: Integer,
        real: Real,
        context: ExecutionContext,
    ): Numeric = commonBehaviour(integer.decimalValue, real.value, context)

    override fun mathFunction(
        real1: Real,
        real2: Real,
        context: ExecutionContext,
    ): Numeric = commonBehaviour(real1.value, real2.value, context)

    /** Implements common behaviour for Integer and Real */
    private fun commonBehaviour(
        dividend: BigDecimal,
        divisor: BigDecimal,
        context: ExecutionContext,
    ): Real =
        // TODO: 25/10/2019 "float_overflow" and "underflow" checks missing (see the standard)
        if (divisor.compareTo(BigDecimal.ZERO) == 0) {
            throwZeroDivisorError(context)
        } else {
            Numeric.of(dividend.div(divisor, MathContext())!!)
        }
}