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

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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 Multiplication : BinaryMathFunction("*") {

    override fun mathFunction(integer1: Integer, integer2: Integer, context: ExecutionContext): Numeric =
        // TODO: 25/10/2019 "int_overflow" check missing (see the standard)
        Numeric.of(integer1.value * integer2.value)

    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)

    /** Implements common behaviour for mixed Integer and Real */
    private fun commonBehaviour(decimal1: BigDecimal, decimal2: BigDecimal): Real =
        // TODO: 25/10/2019 "float_overflow" and "underflow" checks missing (see the standard)
        Numeric.of(decimal1 * decimal2)
}