Hi everybody, I've begun the implementation of inheritance in AngelScript. I know a lot of people have been waiting for this feature so I thought I'd let you guys know the good news. I've actually already checked in a good part of the implementation in the SVN, as work-in-progress for version 2.15.2. It would be good if those of you who plan on using the feature, could start testing it already so that I can work out the kinks even before the final release of 2.15.2 (probably by the end of February). Things that is already working: - single inheritance, where the derived class inherits properties and methods from the parent - overriding inherited methods - polymorphing through the use of virtual methods (all class methods are by default virtual) - implicit cast from derived class to base class - explicit dynamic cast from base class to derived class - save/load bytecode that includes class inheritance Things that still needs to be implemented: - Base class' destructor must be called upon destroying a derived class - Calling the base class' constructor from within the constructor of the derived class - Calling base class' method from within overridden method in derived class Things that won't be implemented (at least not at this moment): - multiple inheritance - inheritance from application registered classes - initialization lists for constructors - non-virtual class methods Please let me know your suggestions and concerns. Regards, Andreas

Wow, that's awesome. I've really waited for that. I used a lot of inheritance in my c++ code last year and dreamed of being able to use inheritance in angelscript as well :)

Just too make shure, I will be able to register classes and their base classes with angelscript and cast instances of those in a script? Can't wait for it.

AngelScript already supports registering class hierarchies with proper casting between base classes and derived classes. You establish the available paths for the casting by registering the asBEHAVE_REFCAST behaviour.

This has actually been available since version 2.13.0, which was released in June last year. :)

What I'm implementing now is inheritance for classes declared in the scripts.

It's a bit surprising that you can't use a derived object with a base reference. Ex:

class A {  void print_me() { print("A\n"); }}class B : A {  void print_me() { print("B\n"); }}void foo(A & in a) {  a.print_me();}void main() {  A a;  B b;  foo(a);  foo(b); // generates a "No matching signatures to 'foo(B&)'"}

WitchLord you are the man!

It's been a few weeks since our very long discussion about persistent script objects, and I have been grinding away at other parts of my project that needed attention.

With them done I came back to revisit my scripting implementation, and low and behold, you implemented the one thing I've been needing!

I will check out the latest SVN when I get home and begin messing with this :) :)

Quote: Original post by SiCrane
It's a bit surprising that you can't use a derived object with a base reference. Ex:

That is indeed surprising. :)

I'll look into this. Thanks for letting me know.

Sounds cool :).
regards.

Progress is continuing...

I've fixed the problem that SiCrane mentioned, and I've implemented the call of the base class' constructor and destructor.

The base class' constructor is called from within a constructor via the keyword super, like this:

class Derived : Base{  Derived(int param)  {    if( param > 0 )      super(4);    else      super();  }}

As you can see the call to the base class' constructor can be made in if-statements, allowing you more flexibility in how you initialize the classes.

If the base class' constructor is not manually called, the compiler will automatically insert a call to the base class' default constructor at the beginning of the constructor.

The last major thing that I need to implement before releasing 2.15.2 is the scoping operator, so that base classes methods can be called from overloaded methods in the derived class.

Regards,
Andreas

So if you had this code:

class Derived : Base{  Derived(int param)  {    if( param > 0 )      super(4);  }}

would the base constructor just not be called if param is 0?

You get a compiler error if not all paths call the constructor. Likewise, you get a compiler error if you attempt to call the constructor multiple times, or in a loop.