Hello!

-
Hello!

So I have this interface in Delphi XE:

IUserList = interface
  ['{A9E4DC2D-CDEA-4B5C-8A68-8086D7800455}']
    function GetUser( const Index : Integer ) : TUserClass;
    procedure NewUser( IP : String );
    procedure AddUser( ID: Integer;Token : String;EmployeeLevel : Integer;ProfileName : String );
    function FindUser( IP : String ) : TUserClass;
    property Users[ Index : Integer ] : TUserClass read GetUser;
  end;

When I try to compile the project, Delphi XE complains that GetUser doesn't have an open bracket. Sigh!

Doesn't make sense to me.

Anybody knows what's going on?

Thanks!

A

Comments

  1. Jeroen Wiert PluimersNovember 2, 2014 at 5:18 AM

    I got `[DCC Error] Unit1.pas(15): E2008 Incompatible types`.
    This works: get rid of the `const`:

    unit Unit1;

    interface

    type
      TUserClass = class

      end;
      IUserList = interface
      ['{A9E4DC2D-CDEA-4B5C-8A68-8086D7800455}']
        function GetUser(  Index : Integer ) : TUserClass;
        procedure NewUser( IP : String );
        procedure AddUser( ID: Integer;Token : String;EmployeeLevel : Integer;ProfileName : String );
        function FindUser( IP : String ) : TUserClass;
        property Users[ Index : Integer ] : TUserClass read GetUser;
      end;

      implementation

    end.

    ReplyDelete
  2. Andrea RaimondiNovember 2, 2014 at 5:28 AM

    Groan... today isn't a good day is it?

    Thanks!

    A

    ReplyDelete
  3. Jeroen Wiert PluimersNovember 2, 2014 at 5:29 AM

    Andrea Raimondi I think it is a known coding convention, but I could not find a documentation link on it yet.

    ReplyDelete
  4. David MillingtonNovember 2, 2014 at 6:33 AM

    I've seen something like this before where the compiler accepted the code, but then the compiled code using the indexed property never called the Get method - silently. That took a while to track down :/

    In that situation removing the const fixed it too.

    ReplyDelete
  5. Bill MeyerNovember 2, 2014 at 8:24 AM

    Jeroen Wiert Pluimers Are you saying, then, that by "convention" you mean that the const specification is illegal there? I think I would spell that "defect"...

    ReplyDelete
  6. Chris RollistonNovember 2, 2014 at 8:39 AM

    Bill Meyer
    The problem is that the property getter includes a const modifier for Index but the property declaration didn't. If you want to make the parameter for the index const, then it needs to be so when declaring the property too:

    property Users[const Index : Integer ] : TUserClass read GetUser;

    ReplyDelete
  7. Bill MeyerNovember 2, 2014 at 8:41 AM

    Chris Rolliston Ah, I see. One of those things I could easily miss. I shall have to see whether MMX handles it properly.

    ReplyDelete
  8. Prakash ShirodkarNovember 3, 2014 at 3:26 AM

    Remove keyword const from parameter declaration 
    e.g.  function GetUser( Index : Integer ) :

    ReplyDelete

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