How to avoid dependency injection in Scala?

Question

I read Dependency Injection Without the Gymnastics PDF which indicates there\'s no need for any fancy DI framework, but it\'s beyond my grasp (at least without concrete examples

Answer 1

You may solve it with self-types.

A depends on both B and C and both B and C depend on D

so one could write this like that:

class A {
  self: B with C => 
}

trait B { 
  self: D => 
}

trait C {
  self: D => 
}

trait D {}

and then on a call side:

val x = new A with BImpl with CImpl with DImpl

but code below won't compile, because dependencies on B,C,D classes not resolved:

val x = new A