Am 30.10.2013 08:47, schrieb Xiangrong Fang:
Hi All,

I have the following class:

type
  generic TVector<T> = class
  private type
    TDataType = array of T;
  private
    FData: TDataType;
    ... ...
  public
    ... ...
    function Slice(APos: Integer = -1; ACount: Integer = -1): TDataType;
  end;

The Slice() method return a portion of the data as a dynamic array.

My question is, as I define TDataType as PRIVATE type, why it is still usable outside of the class? In the main program I did:

type
  TIntVector = specialize TVector<Integer>;
var
  iv: TIntVector;
  ia: array of Integer;
begin
  iv := TIntVector.Create;
  ... ...
  ia := iv.Slice;
end.

This will assign a TDataType (is it TVector$TDataType or TIntVector$TDataType? I don't know) to an "array of Integer". Why this assignment works?

i.e. how does the type system work?!
It's a bit annoying that the usage private/protected types in public/published functions is allowed... (this is however Delphi compatible) Maybe this should be adjusted for non-Delphi modes for language consistency... (maybe at least as a warning which could be elevated to an error if someone wants)

Regards,
Sven
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