bug on virtuality

18 Oct 2008

      Dear list,
today I came across some (I believe) inconsistency related to virtual  
parent classes. The following code exemplifies such bug.
There are three types of classes:
Point -> in principle purely virtual
Point2D and Point3D -> inherit from Point

Point2D and Point3D need to be of the same parental type, so valid  
functions for both of them can be written in a single definition. See  
coordinates(Point p) and coordinates(Point p[]). The chuck interpreter  
complains when passing an array of Point2D or Point3D to the second  
function, claiming there is a type mismatch. In my opinion this should  
not happen. What do you think?

eudard

public class Point
{
   // virtual class
   fun void set(int x, int y){}
   fun void print(){}
}

class Point2D extends Point
{
   int _x;
   int _y;
   fun void set(int x, int y)
   {
     x => _x;
     y => _y;
   }

   fun void print() { <<< _x, _y >>>; }
}

class Point3D extends Point
{
   int _x;
   int _y;
   int _z;
   fun void set(int x, int y, int z)
   {
     x => _x;
     y => _y;
     z => _z;
   }

   fun void print() { <<< _x, _y, _z >>>; }
}

fun void coordinates(Point p)
{
   p.print();
}

fun void coordinates(Point p[])
{
   for (int i; i < p.size(); i++) p[i].print();
}

Point2D p2d;
Point3D p3d;

Point2D p2d_array[2];
Point3D p3d_array[2];

// this works:
coordinates(p2d);
coordinates(p3d);

// this doesn't work
// reason might be due to passing arrays
coordinates(p2d_array);
coordinates(p3d_array);

eduard aylon

Kassen

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