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

[Michael Van Canneyt]

On Wed, 21 Oct 2009, Paul Ishenin wrote:

> Michael Van Canneyt wrote:
>> My only worry now is to make sure that if they are implemented, that we 
>> make the design as clean as possible: e.g. No hardcoded dependencies on 
>> class or
>> interface names.
> We need to count the pros and contras first regards hardcoded names and maybe 
> 'hard coded' code. For example for me  the hardcoded 'Result' identifier for 
> all functions is a big advantage. But you are still using the function names 
> to set the result values I suppose. So during this clean design designing we 
> need to find a compromise between 2 approaches.
>
> for example, would you argue if iterator will be any container type: 
> object/class with the next declaration:
>
> TMyIterator = object
> public
> function StepNext: Boolean;
> property TheCurrentValue: Integer;
>
> iterator MoveNext = StepNext;
> iterator Current = TheCurrentValue;
> end;
>
> When 'iterator MoveNext' or 'iterator Current' are not defined then compiler 
> uses default hardcoded identifiers 'MoveNext' and 'Current'.
>
> This is very like to how you can bind interface methods to the class methods 
> if they are differ.

Hm.  I like this direction of thinking, yes...

What about

   function StepNext: Boolean; iterator 'movenext';
   property TheCurrentValue: Integer; iterator 'current';

or better yet, because it is more strict:

   function StepNext: Boolean; iterator nextvalue;
   property TheCurrentValue: Integer; iterator currentvalue;

In this way, it's more like some extra modifiers. 
(so like safecall, default, stored and whatnot)

It just adds some modifiers, and we're free of hard-coded names.
With one of these I could live :-)

Michael.