Scala Language Var, Val, and Def Named Parameters
Example
When invoking a def, parameters may be assigned explicitly by name. Doing so means they needn't be correctly ordered. For example, define printUs() as:
// print out the three arguments in order.
def printUs(one: String, two: String, three: String) =
println(s"$one, $two, $three")
Now it can be called in these ways (amongst others):
printUs("one", "two", "three")
printUs(one="one", two="two", three="three")
printUs("one", two="two", three="three")
printUs(three="three", one="one", two="two")
This results in one, two, three being printed in all cases.
If not all arguments are named, the first arguments are matched by order. No positional (non-named) argument may follow a named one:
printUs("one", two="two", three="three") // prints 'one, two, three'
printUs(two="two", three="three", "one") // fails to compile: 'positional after named argument'
