Scala：BigDecimal是数字的隐式证据

Question

How does scala.math.BigDecimal is implicitly converted to scala.math.Numeric ?

For example : for Int chain of implicit conversion is traced like: Int to RichInt (conversion defined in Predef ) and method

protected implicit def num: Numeric[T]

from parent class scala.runtime.ScalaNumberProxy .

The tricky part with scala.math.BigDecimal is that it does not have any wrappers.

Thanks in advance.

Answer 1

Numeric[T] is a type class, so it doesn't convert the BigDecimal to a Numeric ; instead, there is an implicit Numeric[BigDecimal] defined which contains the implementation of Numeric which operates on BigDecimal values.

The implicit is defined here - https://github.com/scala/scala/blob/2.12.x/src/library/scala/math/Numeric.scala#L187