Hi,

I'm hoping someone could help me understand the pros and cons of the way some of the code in the book is written.

Often you see code like this:

trait TaxCalculation {
  type S <: TaxCalculationTable
  val table: S
}

What is the benefit of using a polymorphic type like this rather than writing:

trait TaxCalculation {
  val table: TaxCalculationTable
}

Or even:

trait TaxCalculation[S <: TaxCalculationTable] {
  val table: S
}

Similarly for function signatures:

def f[A <: Foo](a: A)

Versus:

def f(a: Foo)

Thanks for any insights,

Ashlin.

+1 I have the same question

159028 wrote:Hi,

I'm hoping someone could help me understand the pros and cons of the way some of the code in the book is written.

Often you see code like this:

trait TaxCalculation {
  type S <: TaxCalculationTable
  val table: S
}

What is the benefit of using a polymorphic type like this rather than writing:

trait TaxCalculation {
  val table: TaxCalculationTable
}

Or even:

trait TaxCalculation[S <: TaxCalculationTable] {
  val table: S
}

Similarly for function signatures:

def f[A <: Foo](a: A)

Versus:

def f(a: Foo)

Thanks for any insights,

Ashlin.