CODEWITHSUNDEEP
scalabigdecimalzero
pr1001
pr1001

Reputation: 21962

Why doesn't Scala's BigDecimal have a ZERO?

It's easy enough to create:

object zero extends BigDecimal(java.math.BigDecimal.ZERO)

I'm just wondering whether this was an oversight, or if there was a conscious decision to not add this and, if so, are there reasons why I should avoid the code above. Perhaps having to do with the MathContext?

Upvotes: 11

Views: 5197

Answers (3)

Anthony Accioly
Anthony Accioly

Reputation: 22461

Resurrection of an old thread for the sake of completeness. Scala actually has something similar to java BigDecimal.ZERO, you can access it with BigDecimalIsFractional.zero.

As previous answers already pointed out most of the time the literal 0 will be fine. Having said that, Context Bounds can be useful with generic code:

def zero[T: Numeric](): Unit = {
  val evidence = implicitly[Numeric[T]]
  val zero = evidence.zero
  println(s"${zero} is a ${zero.getClass.getSimpleName} defined at ${evidence.getClass.getName}")
}

zero[BigDecimal]() // 0 is a BigDecimal defined in scala.math.Numeric$BigDecimalIsFractional$
zero[Double]() // 0.0 is a Double defined in scala.math.Numeric$DoubleIsFractional$
zero[Int]() // 0 is a Integer defined at scala.math.Numeric$IntIsIntegral$

Upvotes: 1

Luigi Plinge
Luigi Plinge

Reputation: 51109

I'd think it's because usually you don't need it. Whereas in Java you need to type something like

BigDecimal b = new BigDecimal(1.23).add(BigDecimal.ZERO);

in Scala, there are number conversions that mean you can write

val b = BigDecimal(1.23) + 0

You can also write it simply as BigDecimal(0). If you're instantiating that a lot you might want to cache it as a named value (as for any other number), but you won't normally need to, and I think it helps simplify the API if you remove special cases that you have to remember.

Upvotes: 7

Ian McLaird
Ian McLaird

Reputation: 5585

If I had to guess, it's because the expected way to get that value would be like this:

val zero: BigDecimal = 0

Upvotes: 17

Related Questions