oop is as

Smart pascal source code


{
  Demo: Object Orientated Programming (OOP)

}
type
  AClass = class
    function Q: string;
  end;

type
  BClass = class(AClass)
    function Q: string;
  end;

type
  CClass = class
    function Q: string;
  end;

function AClass.Q: string;
begin
  Result := 'AClass.Q: Static method';
end;

function BClass.Q: string;
begin
  Result := 'BClass.Q: Static method';
end;

function CClass.Q: string;
begin
  Result := 'CClass.Q: Static method';
end;

var objA, objB: AClass;

objA := AClass.Create;
objB := BClass.Create;

if objA is AClass then
  WriteLn('objA is AClass');
if objA is BClass then
  WriteLn('objA is BClass');
if objA is CClass then
  WriteLn('objA is CClass');

if objB is AClass then
  WriteLn('objB is AClass');
if objB is BClass then
  WriteLn('objB is BClass');
if objB is CClass then
  WriteLn('objB is CClass');

WriteLn((objA as AClass).Q);
try
  WriteLn((objA as BClass).Q);
except
  WriteLn('objA isn''t BClass');
end;
try
  WriteLn((objA as CClass).Q);
except
  WriteLn('objA isn''t CClass');
end;

WriteLn((objB as AClass).Q);
WriteLn((objB as BClass).Q);
try
  WriteLn((objB as CClass).Q);
except
  WriteLn('objB isn''t CClass');
end;

{<<< RESULT - CONSOLE LOG >>>
-----------------------------
Errors >>>>
Warning: Incompatible types: "AClass" and "CClass" [line: 42, column: 9]
Warning: Incompatible types: "AClass" and "CClass" [line: 46, column: 9]
Result >>>>
objA is AClass
objB is AClass
objB is BClass
AClass.Q: Static method
objA isn't BClass
objA isn't CClass
AClass.Q: Static method
BClass.Q: Static method
objB isn't CClass

-----------------------------
{<<<<<<<<< THE END >>>>>>>>>}

var CClass = {
   $ClassName:"CClass",$Parent:TObject
   ,$Init:function ($) {
      TObject.$Init($);
   }
   ,Q:function(Self) {
      return "CClass.Q: Static method";
   }
   ,Destroy:TObject.Destroy
};
var AClass = {
   $ClassName:"AClass",$Parent:TObject
   ,$Init:function ($) {
      TObject.$Init($);
   }
   ,Q$1:function(Self) {
      return "AClass.Q: Static method";
   }
   ,Destroy:TObject.Destroy
};
var BClass = {
   $ClassName:"BClass",$Parent:AClass
   ,$Init:function ($) {
      AClass.$Init($);
   }
   ,Q$2:function(Self) {
      return "BClass.Q: Static method";
   }
   ,Destroy:TObject.Destroy
};
var objA = null;
var objB = null;

/* <<< main JS >>> */

   objA = TObject.Create($New(AClass));
   objB = TObject.Create($New(BClass));
   if ($Is(objA,AClass)) {
      WriteLn("objA is AClass");
   }
   if ($Is(objA,BClass)) {
      WriteLn("objA is BClass");
   }
   if ($Is(objA,CClass)) {
      WriteLn("objA is CClass");
   }
   if ($Is(objB,AClass)) {
      WriteLn("objB is AClass");
   }
   if ($Is(objB,BClass)) {
      WriteLn("objB is BClass");
   }
   if ($Is(objB,CClass)) {
      WriteLn("objB is CClass");
   }
   WriteLn(AClass.Q$1(objA));
   try {
      WriteLn(BClass.Q$2($As(objA,BClass)));
   } catch ($e) {
      WriteLn("objA isn't BClass");
   }
   try {
      WriteLn(CClass.Q($As(objA,CClass)));
   } catch ($e) {
      WriteLn("objA isn't CClass");
   }
   WriteLn(AClass.Q$1(objB));
   WriteLn(BClass.Q$2($As(objB,BClass)));
   try {
      WriteLn(CClass.Q($As(objB,CClass)));
   } catch ($e) {
      WriteLn("objB isn't CClass");
   }