How can I refactor out the required else clause?

Question

I have a C# method that looks a bit like this:

bool Eval() {
  // do some work
  if (conditionA) {
     // do some work
     if (conditionB) {
       // do s         


        

Answer 1

You could make your code into a kind of truth table, which depending on your real-world case might make it more explicit:

let condA() = true
let condB() = false
let condC() = true

let doThingA() = Console.WriteLine("Did work A")
let doThingB() = Console.WriteLine("Did work B")
let doThingC() = Console.WriteLine("Did work C")

let Eval() : bool =
    match condA(), condB(), condC() with
    | true,  false, _     -> doThingA();                           false;
    | true,  true,  false -> doThingA(); doThingB();               false;
    | true,  true,  true  -> doThingA(); doThingB(); doThingC();   true;
    | false, _,     _     ->                                       false;