fpc 3.2.2 - Forward a Class - how to ?

[paule32]

hello, how can I "forward" a class ?

given two classes:

type TBar = class;  // this give me: Error: forward declaration of
                            // class "TBar" must be resolved here

type TFoo = class(TBar)
       public
           procedure setAHandle(AHandle: Integer);
       end;

type TBar = class(TBaz)
       private
         AHandle: Integer;
       end;

[Awkward]

You must define forward class in same "type" block

[paule32]

following Code produce the Compiler Error:

Code: Pascal  [Select][+][-]

1. type
2.   TPersistent = class(TObject)
3.   public
4.     constructor Create;
5.     destructor Destroy; override;
6.    
7.     class function ClassName: String; stdcall; virtual;
8.   end;
9.  
10. type TComponent = class;
11.   TControl = class(TComponent)
12.   private
13.     FAlign: TAlign;
14.     FClientHeight: Integer;
15.     FClientWidth: Integer;
16.     FHeight: Integer;
17.     FLeft: Integer;
18.     FTop: Integer;
19.     FWidth: Integer;
20.   protected
21.     function GetClientHeight: Integer;
22.     function GetClientWidth: Integer;
23.    
24.     procedure SetClientHeight(AValue: Integer);
25.     procedure SetClientWidth (AValue: Integer);
26.    
27.     procedure SetAlign(AValue: TAlign);
28.   public
29.     constructor Create(AOwner: TComponent);
30.     destructor Destroy; override;
31.    
32.     class function ClassName: String; stdcall; virtual;
33.   published
34.     property Align: TAlign read FAlign write SetAlign default alNone;
35.     property Height: Integer read FHeight write FHeight;
36.     property Left: Integer read FLeft write FLeft;
37.     property Top: Integer read FTop write FTop;
38.     property Width: Integer read FWidth write FWidth;
39.   end;
40.  
41.   TComponent = class(TPersistent)
42.   private
43.     FArray: array of TComponent;
44.     FOwner: TComponent;
45.     FIndex: Integer;
46.     FTag: NativeInt;
47.   protected
48.     function  GetComponent(I: Integer): TComponent;
49.     function  GetComponentCount: Integer;
50.     function  GetComponentIndex: Integer;
51.     function  GetComponentOwner: TComponent;
52.    
53.     procedure SetComponentIndex(AValue: Integer);
54.     procedure SetComponentOwner(AOwner: TComponent);
55.   public
56.     constructor Create(AOwner: TComponent); virtual;
57.     destructor Destroy; override;
58.    
59.     class function ClassName: String; stdcall; virtual;
60.   published
61.     property ComponentCount: Integer read GetComponentCount;
62.     property ComponentIndex: Integer read GetComponentIndex write SetComponentIndex;
63.     property Components[I: Integer]: TComponent read GetComponent;
64.     property Owner: TComponent read FOwner;
65.     property Tag: NativeInt read FTag write FTag default 0;
66.   end;
67.  

[Zvoni]

type TComponent = class;
  TControl = class(TComponent)
  private
    FAlign: TAlign;

[paule32]

ok, thank you.
it works like a charm.