Scala Evaluation Rules

evaluation-rules.sc

def example = 2      // evaluated when called
val example = 2      // evaluated immediately
lazy val example = 2 // evaluated once when needed

def square(x: Double)    // call by value
def square(x: => Double) // call by name
def myFct(bindings: Int*) = { ... } // bindings is a sequence of int, containing a varying # of arguments

• Call by value: evaluates the function arguments before calling the function
• Call by name: evaluates the function first, and then evaluates the arguments if need be