[fpc-devel] New feature discussion: for-in loop

[Paul Ishenin]

Graeme Geldenhuys wrote:
> Also, I referred to them in my implementation as Iterators - as per
> the Iterator design pattern. How does Enumerator differ from Iterator?
>   
I have looked at you interfaces. They are needs to be changed a bit to 
use then in the for-in loop. For example:

  ITBIterator = interface(IInterface)
  ['{9C2BC10D-54C8-4B59-88B5-A564921CF0E3}']
    function    HasNext: Boolean;
    function    Next: TObject;
    function    HasPrevious: Boolean;
    function    Previous: TObject;
  end;

To use it in the for-in loop you need to add a function MoveNext: 
Boolean (you can choose any other name but you need to mark it using 
'enumerator MoveMext' modifier) and property Current: TObject (you can 
choose any other name but you need to mark it using 'enumerator Current' 
modifier).

Look at 
http://svn.freepascal.org/svn/fpc/branches/paul/features/tests/test/tforin8.pp 
and 
http://svn.freepascal.org/svn/fpc/branches/paul/features/tests/test/tforin9.pp 
for examples.

Best regards,
Paul Ishenin.