public override HeronValue Eval(VM vm)
{
HeronValue a = operand1.Eval(vm);
HeronValue b = operand2.Eval(vm);
switch (opcode)
{
case OpCode.opEq:
return(new BoolValue(a.Equals(b)));
case OpCode.opNEq:
return(new BoolValue(!a.Equals(b)));
case OpCode.opIs:
{
TypeValue tv = b as TypeValue;
if (tv == null)
{
throw new Exception("The second argument of the 'is' operator must be a type");
}
return(new BoolValue(a.Is(tv.Type)));
}
case OpCode.opAs:
{
HeronType t = b as HeronType;
if (t == null)
{
throw new Exception("The 'as' operator expects a type as a right hand argument");
}
HeronValue r = a.As(t);
if (r != null)
{
return(r);
}
if (t is InterfaceDefn && a is ClassInstance)
{
DuckValue dv = new DuckValue(a as ClassInstance, t as InterfaceDefn);
return(dv);
}
throw new Exception("Failed to convert " + a.Type.name + " to a " + t.name);
};
}
return(a.InvokeBinaryOperator(vm, opcode, b));
}