...not a polymorphic type

Monkey Forums/Monkey Programming/...not a polymorphic type

Xaron

(Posted 2012) [#1]

Hi all,

I just try to introduce new classes for the GLFW target but run into some polymorphic trouble.

Here's my class test.cpp

class Test_Bla
{
  static void Blub()
  {
  }
};

Here's the Monkey interface testbla.monkey:

Strict

Private

Import "test.cpp"

Public

Extern

Class Bla = "Test_Bla"
  Method Blub:Void()
End Class

and here's my main code:

Strict

Import mojo
Import testbla

Function Main:Int()
  New TestApp()
  Return 0
End Function

Class TestApp Extends App
  Field testbla:Bla = Null

  Method OnCreate:Int()
    SetUpdateRate(30)
    
    testbla = New Bla()
    Return 0
  End Method

  Method OnUpdate:Int()
    If( KeyHit( KEY_ESCAPE ) )
      Error ""
    End If
    
    Return 0
  End Method
  
  Method OnSuspend:Int()
    Return 0
  End Method
  
  Method OnResume:Int()
    Return 0
  End Method

  Method OnRender:Int()
    Cls
    Return 0
  End Method
End Class

For GLFW this fails compiling with:

(ClCompile target) ->
..\main.cpp(204): error C2683: 'dynamic_cast' : 'Test_Bla' is not a polymorphic type [D:\Projekte\mnet\examples\test.build\glfw\vc2010\MonkeyGame.vcxproj]
..\main.cpp(191): error C2683: 'dynamic_cast' : 'Test_Bla' is not a polymorphic type [D:\Projekte\mnet\examples\test.build\glfw\vc2010\MonkeyGame.vcxproj]

I understand the error message because line 204 of the main.cpp just tries to do a dynamic_cast which obviously doesn't work with a static object:

gc_object *p=dynamic_cast<gc_object*>(rhs);

But... how can I avoid it?

How do you "diddy-guys" handle this for GLFW?

Goodlookinguy

(Posted 2012) [#2]

I'd say it's this line

Method Blub:Void()

In your code it's a static method, a.k.a function in monkey.

This will probably fix it, though I've never tested it or imported a function within a class.

Function Blub:Void()

It'd probably be easier to just do this though.

Function Blub:Void() = "Test_Bla::Blub"

Don't mind that last part. Anyways...

Xaron

(Posted 2012) [#3]

Yep I know. "Avoiding" the creation of the class it works using something like

Function Blub:Void() = "Test_Bla::Blub"

directly to get access to the static method... But it would be nice to have a real object.

In diddy it's just done via that function solution.

Goodlookinguy

(Posted 2012) [#4]

Oh, you know what, looking in monkey/lang.monkey there's some pretty weird stuff going on that might help in finding the answer to this dilemma. Though I can't really say for sure, considering that's part of the core language.

Xaron

(Posted 2012) [#5]

rofl, thanks! Will take a look! :)

Class @Object Extends Null="Object"

Ahem.... Alright. *gg*

Xaron

(Posted 2012) [#6]

Guess what? That compiles:


Class @Bla Extends Null = "Test_Bla"
  Function Blub:Void()
End Class

Uh oh... now I have to try if it not only compiles but runs as well.

Xaron

(Posted 2012) [#7]

Fantastic. Thanks for pointing me to that, Goodlookinguy!

Sockets for GLFW are working now (TCP Server as well as client), yay! Now to Android. :)

Samah

(Posted 2012) [#8]

Externed C++ classes need to extend public Object if you want to use any of the Monkey-related stuff (GC, etc.)

class Foo : public Object {
};

This was my experience from porting Lua, at least.

Xaron

(Posted 2012) [#9]

Thanks Samah, it works with the code above. Might be some ugly void pointer stuff deriving from Null? LOL.