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Undocumented Delphi 8 Language Changes 2

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Undocumented Delphi 8 Language Changes 2

Wed, 26 May 2004 @ 7:00 AM
  • Comments 2

What is the difference in the code shown below in Delphi 7, and Delphi 8?

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program Project2;
{$APPTYPE CONSOLE}
uses
  SysUtils;
 
type
  TSome = procedure of object;
 
  TSomeObj = class
  private
    FOnSome: TSome;
    procedure MySome1;
  public
    procedure DoSome;
    property OnSome: TSome read FOnSome write FOnSome;
  end;
 
{ TSomeObj }
 
procedure TSomeObj.DoSome;
begin
  if Assigned(FOnSome) then
    FOnSome;
end;
 
procedure TSomeObj.MySome1;
begin
end;
 
procedure OutsideSome1;
begin
end;
 
var
  SomeObj: TSomeObj;
 
begin
  SomeObj := TSomeObj.Create;
  SomeObj.OnSome := OutsideSome1;
end.
Leave a Comment
  • 26 May 2004 6:01 PM
    Assigning a method pointer to a global routine isn't allowed in D7, but D8 currently permits it:

    SomeObj.FOnSome := OutsideSome1;

    This is most probably because in D8 global routines are implemented as static class methods of the compiler generated Unit class, and .NET delegates are compatible with both instance and static class methods (where the instance part is nil).

    AFAIK, this is considered a bug in the D8 language, and might very well be disallowed in a future version.
  • 26 May 2004 6:14 PM
    ;o) Hallvard, thanks for your reply. Your reply also made me realized I should have written SomeObj.OnSome, instead of SomeObj.FOnSome, so I've updated the article, and I've taken the liberty to update your comment.

    Well, look out for more undocumented language changes articles. ;o)
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