When is a def assigned to his constant value in a derived class ?

Question

Hi ,
I encountered some strange thing in my app when using a def in a derived class from abstract base class. (dived by zero exception)
I point it out here using a small code snippet which reflects the problem in my app:
public abstract class Base{
    public var varBase;
public class BaseDerived extends Base{
    def const = 1;
    var temp : Double;
    public override var varBase on replace{
        temp = varBase / const;
        println("{const}");
function run(){
       var test = BaseDerived {varBase:10};
       println ("{test.temp}");
result is:
0
InfinityI assumed that all "defs" will already be assigned before any single use in the code when creating an object. If I put the "def" in the base class all works fine. But apparently this is not case when implementing an abstract class and use a def in that class.
What am I missing here ?
thanks
Guy

Answer 1

I changed the code to:
public mixin class Base {
    public var varBase;
    init { println("Base Init"); }
    postinit { println("Base PostInit"); }
public class BaseDerived extends Base {
    def constant = 1;
    var temp: Double;
    init { println("BaseDerived Init"); }
    postinit { println("BaseDerived PostInit"); }
    public function showVar(msg: String) {
        println("# BaseDerived ({msg})");
        println("VarBase: {varBase}");
        println("Constant: {constant}");
        println("Temp: {temp}");
    public override var varBase on replace {
        showVar("Before computation");
        temp = varBase / constant;
        showVar("After computation");
function run() {
    var test = BaseDerived { varBase: 10 };
    test.showVar("Created test");
}The output of abstract class:
# BaseDerived (Before computation)
VarBase: 10.0
Constant: 0 --> BAD
Temp: 0.0
# BaseDerived (After computation)
VarBase: 10.0
Constant: 0
Temp: Infinity
Base Init
BaseDerived Init
Base PostInit
BaseDerived PostInit
# BaseDerived (Created test)
VarBase: 10.0
Constant: 1
Temp: Infinity --> NOK and replace not newly triggeredWhile the mixin base class indeed solves it:
# BaseDerived (Before computation)
VarBase: 10.0
Constant: 1 --> constant here already been assigned
Temp: 0.0
# BaseDerived (After computation)
VarBase: 10.0
Constant: 1
Temp: 10.0
Base Init
BaseDerived Init
Base PostInit
BaseDerived PostInit
# BaseDerived (Created test)
VarBase: 10.0
Constant: 1
Temp: 10.0 --> OKThanks for the quick goodies !
I just need to read something on what "mixin" differs from abstract.
cheers
Guy