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Inherited methods not used to complete Interface

Monkey Forums/Monkey Programming/Inherited methods not used to complete Interface

Shagwana(Posted 2013) [#1]
Looks like inherited methods are not used to determine if a interface has been implemented. The following code generates a error when it should not as the Interface has been implemented in the parent class.

Strict

Interface inter_i

	Method draw:Void(n:Int)

End Interface

Class lvl1_c 

	Method draw:Void(n:Int)
		Print "levl1_c printing - "+n
	End Method
		
End Class


Class lvl2_c Extends lvl1_c	Implements inter_i

	'draw is implemented in lvl1_c


'	Method draw:Void(n:Int)'
'		Print "levl2_c printing - "+n
'	End Method


End Class


Function Main:Int()

	Local a:inter_i = New lvl2_c
	a.draw(34)
	
	Return 0
End Function


Of note, if you set the parent class as implementing the Interface. The Child classes inherit this interface as well.


Gerry Quinn(Posted 2013) [#2]
I think that's the way its supposed to work. Isn't it the point of interfaces that you have to implement them in every class that honours them?


Shagwana(Posted 2013) [#3]
It is implemented by inheritance.


marksibly(Posted 2013) [#4]
This is a limitation of the way interfaces work in some target languages (C#/Java I think) so is therefore a limitation of Monkey.

Basically, interface methods must be implemented in the 'implements' class (or, strictly speaking, a subclass).

I suspect it's an efficiency thing, so that interface methods are all group into consecutive slots in a 'vtable' somewhere/somehow...


Samah(Posted 2013) [#5]
public interface Inter
{
  public void blah( );
}

public class A
{
  public void blah( )
  {}
}

public class B extends A implements Inter
{
}

Works fine in Java.


Shagwana(Posted 2013) [#6]
Just for the record (if anyone comes across this in the future).

You can sort of get around this by making some dummy functions/methods that call the super version of self.

So the code above would look like...
Class lvl2_c Extends lvl1_c Implements inter_i

	'draw is implemented in lvl1_c

	Method draw:Void(n:Int)
		Super.draw(n)
	End Method

End Class


As I think of this, is this not something the compiler could handle for us all auto-magic like?