When to use the equals sign in a Scala method declaration?

Question

With equals sign:

object HelloWorld {
  def main(args: Array[String]) = {
    println(\"Hello!\")
  }
}

Without equals sign:

Answer 1

For methods, Scala Style Guide recommends the equals syntax as opposed to procedure syntax

Procedure Syntax

Avoid the procedure syntax, as it tends to be confusing for very little gain in brevity.

// don't do this
def printBar(bar: Baz) {
  println(bar)
}
// write this instead
def printBar(bar: Bar): Unit = {
  println(bar)
}