Overloading with different parameters

Monkey Forums/Monkey Programming/Overloading with different parameters

chimaera

(Posted 2014) [#1]

Hi,

I was searching the forums but I am not sure if I found a "suitable" explanation (or at least one that I could understand). I thought one was able to overload methods with different parameters like this:

Class c_baseClass
   Method change() Abstact
End

Class c_classA Extends c_baseClass
   Method change(param:int)
End

Class c_classB Extends c_baseClass
   Method change(param:int, param2:int)
End

I am getting an error here...Any ideas?

Trez	(Posted 2014) [#2]

Your Methods do not have an End Statement

Class c_baseClass
   Method change() Abstact
   End
End

Class c_classA Extends c_baseClass
   Method change(param:int)
   End
   
End

Class c_classB Extends c_baseClass
   Method change(param:int, param2:int)
   End  
End

chimaera

(Posted 2014) [#3]

Hi Trez,

Totally true but that was just an example. Even with the End statements I don't believe that this kind of overloading is allowed.

ziggy

(Posted 2014) [#4]

Extending classes are not allowed to generate new overloads in Monkey.

Jesse

(Posted 2014) [#5]

This would work:

Class c_baseClass Abstract
   Method change(); End
   Method change(param:Int); End
   Method change(param:Int, param2:Int); End
End

Class c_classA Extends c_baseClass
   Method change(param:Int)
   End Method
End

Class c_classB Extends c_baseClass
   Method change(param:Int, param2:Int)
   End Method
End

@Trez

Class c_baseClass
   Method change() Abstact
End

there is nothing wrong with that code and is the correct way of using it.

chimaera

(Posted 2014) [#6]

Ah! Thanks Jesse! That will totally solve my problem.

Great ideas and help as usually around here.

ziggy

(Posted 2014) [#7]

Take into account that, in Monkey, if you override a method with several overloads, only the overriden ones are available to be called later.

Exampe:

Class A
    Method DoSomething(value1:Int)
    end
    Method DoSomething(value1:Int, value2:Int)
    end
End

Class B extends A
    Method DoSomething(value1:Int)
    End
End

Function Main()
    Local a:=New A
    a.DoSomething(10)
    a.DoSomething(10,20)
    Local b:=New B
    b.DoSomething(10)
    b.DoSomething(10,20) '<--- This fails
End

Jesse

(Posted 2014) [#8]

but this work:

Class A
    Method DoSomething(value1:Int)
    end
    Method DoSomething(value1:Int, value2:Int)
    end
End

Class B extends A
    Method DoSomething(value1:Int)
    End
End

Function Main()
    Local a:=New A
    a.DoSomething(10)
    a.DoSomething(10,20)
    Local b:A=New B
    b.DoSomething(10)
    b.DoSomething(10,20) '<--- This don't fail
End

Danilo

(Posted 2014) [#9]

Take into account that, in Monkey, if you override a method with several overloads, only the overriden ones are available to be called later.

Exampe:

Class A
    Method DoSomething(value1:Int)
    end
    Method DoSomething(value1:Int, value2:Int)
    end
End

Class B extends A
    Method DoSomething(value1:Int)
    End
End

Function Main()
    Local a:=New A
    a.DoSomething(10)
    a.DoSomething(10,20)
    Local b:=New B
    b.DoSomething(10)
    b.DoSomething(10,20) '<--- This fails
End

Looks like a bug. Class B inherits/extends Class A, so Class B contains everything from Class A.

The error message says "--> Unable to find overload for DoSomething(Int,Int)."
If it can't find the correct overload in Class B, it should check in the parent Class A,
and there it is.

This works correctly (it finds the correct overloads):

Class A
    Method DoSomething(value1:Int)
    End
    Method DoSomething(value1:Int, value2:Int)
    End
End

Class B extends A
End

Function Main()
    Local a:=New A
    a.DoSomething(10)
    a.DoSomething(10,20)
    Local b:=New B
    b.DoSomething(10)
    b.DoSomething(10,20)
End

Overriding both methods works, too:

Class A
    Method DoSomething(value1:Int)
    End
    Method DoSomething(value1:Int, value2:Int)
    End
End

Class B extends A
    Method DoSomething(value1:Int)
    End
    Method DoSomething(value1:Int, value2:Int)
    End
End

Function Main()
    Local a:=New A
    a.DoSomething(10)
    a.DoSomething(10,20)
    Local b:=New B
    b.DoSomething(10)
    b.DoSomething(10,20)
End

Doesn't make sense that it fails when out-commenting one method in Class B.

chimaera

(Posted 2014) [#10]

Regarding your to 2nd code snippet. Are you sure that this is actually a problem?

In code snippet #2 you do not actually do any overloading in Class B. You are only extending Class A which means that Class B will inherit the methods from Class A. So I believe that there is no overloading here, only inheritance. So I believe it works as intended.

ziggy

(Posted 2014) [#11]

Looks like a bug. Class B inherits/extends Class A, so Class B contains everything from Class A.

Yes, it looks like a bug but it's how it's actually implemented. When Trans solves overloading on a method, it iterates through the inheritance chain and, in the first level it finds a method declaration, it gets all possible overloads (without further iterating the inheritance chain). Not a big issue if you know it, but not as nice as it could possibly be. It got me some Jungle iterations to get this right on the intellisense!