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

[Michael Van Canneyt]

On Tue, 20 Oct 2009, Paul Ishenin wrote:

> Hello,  FPC developers' list.
>
> I think we can close 'sealed/abstract class' page and open another 
> interesting topc.
>
> It is obvious you are full of energy to discuss new language features.
>
> The next feature which we should think of is for-in loop: 
> http://wiki.lazarus.freepascal.org/for-in_loop
>
> There you can find:
> 1. Delphi implementation details
> 2. Proposed extended syntax
> 3. Proposed compiler implementation
>
> While discussion please try to have delphi compatibility in the mind.

At least one of the reasons we never did implement for-in is the absolutely
horrible and totally wrong idea to use classes/interfaces for this, to which
I seriously objected.

The guy who thought of that should be shot, hanged, guillotined and poisoned. 
(you pick your order) It is a total negation of everything that pascal stands for:
let a language feature (for in) depend on a user-class implementation.

I can understand
   for y in enumerated do
or
   For y in set do
or
   For Y in range do
Because this seems a natural extension of loops to enumerates (and even
then) But not ever the class-based one.

Michael.