Accessing a Class Member from a First-Class Function

Question

I have a case class which takes a list of functions:

case class A(q:Double, r:Double, s:Double, l:List[(Double)=>Double])

I have over 20 functions defined. Some of these functions have their own parameters, and some of them also use the q, r, and s values from the case class. Two examples are:

def f1(w:Double) = (d:Double) => math.sin(d) * w
def f2(w:Double, q:Double) = (d:Double) => d * q * w

The problem is that I then need to reference q, r, and s twice when instantiating the case class:

A(0.5, 1.0, 2.0, List(f1(3.0), f2(4.0, 0.5))) //0.5 is referenced twice

I would like to be able to instantiate the class like this:

A(0.5, 1.0, 2.0, List(f1(3.0), f2(4.0))) //f2 already knows about q!

What is the best technique to accomplish this? Can I define my functions in a trait that the case class extends?

EDIT: The real world application has 7 members, not 3. Only a small number of the functions need access to the members. Most of the functions don't care about them.

Answer 1

If q in f2 is always referring to the q in you case class, then one quick hack :

trait TraitA {                                                                                       
  def q:Double                                                                                       
  def r:Double                                                                                       
  def s:Double                                                                                       

  def f1(w:Double) = (d:Double) => math.sin(d) * w                                                   
  def f2(w:Double) = (d:Double) => d * q * w                                                         
}                                                                                                    

case class A(q:Double, r:Double, s:Double, l:List[(Double)=>Double]=Nil) extends TraitA              

val a=new A(0.5, 1.0, 2.0){override val l= List(f1(3.0), f2(4.0))}