FPC generics: circular type reference?

[serge_t]

Hello,

Is it possible to implement the circular type reference within the generic type?
Following example doesn't compile with FPC 2.6.4 (Lazarus 1.2.6 Win32).

Code: [Select]

  generic TGItem<T> = class
  private type
    TGItemSpec = specialize TGItem<T>;
  private var
    FValue: T;
    FLeft, FRight: TGItemSpec;
  public
    property Value: T read FValue write FValue;
  end;


Code: [Select]

project1.lpr(7,29) Error: Illegal expression
project1.lpr(7,35) Error: Specialization is only supported for generic types

[Blaazen]

Your code compiles well in 3.1.1 (only Note: private fields FLeft, FRight never used). There were many generic improvements that are not included in 2.6.4 yet.
Use trunk or wait for fpc 3.0.

[serge_t]

Thank for response.
 
Is it possible to use FPC 3.x with Lazarus?
We have many applications built with LCL so migrating is required in this case.

[Blaazen]

Yes, Lazarus trunk works with FPC trunk.

See my footer: Lazarus 1.5 r48240M FPC 3.1.1 30069 x86_64

[serge_t]

Ok, we will waiting for 1.5 release 

P.S. Generic tree implementation for FPC 2.6.4 without circular type references is here
http://arbinada.com/main/node/1430