Clojure's 'let' equivalent in Scala

Question

Often I face following situation: suppose I have these three functions

def firstFn: Int = ...
def secondFn(b: Int): Long = ...
def thirdFn(x: Int, y: Long, z:         


        

Answer 1

Here's an option you may have overlooked.

def calculate(a: Long)(i: Int = firstFn)(j: Long = secondFn(i)) = thirdFn(i,j,j+a)

If you actually want to create a method, this is the way I'd do it.

Alternatively, you could create a method (one might name it let) that avoids nesting:

class Usable[A](a: A) {
  def use[B](f: A=>B) = f(a)
  def reuse[B,C](f: A=>B)(g: (A,B)=>C) = g(a,f(a))
  // Could add more
}
implicit def use_anything[A](a: A) = new Usable(a)

def calculate(a: Long) =
  firstFn.reuse(secondFn)((first, second) => thirdFn(first,second,second+a))

But now you might need to name the same things multiple times.