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

/**
 * Implementation of `'-'/2` arithmetic functor
 *
 * @author Enrico
 */
object Subtraction : BinaryMathFunction("-") {
    override fun mathFunction(
        integer1: Integer,
        integer2: Integer,
        context: ExecutionContext,
    ): Numeric =
        Numeric.of(
            integer1.value - integer2.value,
        ) // TODO: 24/10/2019 "int_overflow" check missing (see the standard)

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

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

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

    /** Method implementing the behaviour when the two numbers are of different types */
    private fun commonBehaviour(
        decimal1: BigDecimal,
        decimal2: BigDecimal,
    ) = Numeric.of(
        decimal1 - decimal2,
    ) // TODO: 24/10/2019 "float_overflow" and "underflow" checks missing (see the standard)
}