Hi There,

I encountered a problem writing enumerator for my generic tree. The enumerator class looks like this:

  TTreapEnumerator = class
    FStack: TStack;
    FCurrent: TTreap.PNode;
  public
    constructor Create(ANode: TTreap.PNode);
    destructor Destroy; override;
    function MoveNext: Boolean;
    property Current: TTreap.PNode read FCurrent;
  end;

And the error message I got is:

/home/xrfang/git/fpcollection/src/units/treap.pas(363,45) Error: Incompatible type for arg no. 1: Got
"THistogram.TTreap$Char$LongInt.PNode", expected "TTreap.PNode"

i.e. the enumerator expected a generic PNode, but the given node is a specialized one. How to write enumerators for generic classes?

Thanks!

Make the enumerator class nested in the generic class. Inspiration: http://svn.freepascal.org/svn/fpc/trunk/packages/fcl-stl/src/gvector.pp