08.03.2011 15:24, Sven Barth wrote:
1. As I'm going to implement record helpers in the next time I've noticed that I need the modeswitch for advanced records only for declaring such a record. So how should I proceed regarding record helpers: Should the declaration of record helpers be restricted to that mode switch or should I allow it always?
They should be restricted as advanced records.
2. I've done some tests regardings generics in Delphi XE and have found out, that the following example does not compile there: === source begin === TFoo<T> = class Field: T; end; TFooInteger = TFoo<Integer>; TFooHelper = class helper for TFooInteger end; === source end === The compiler complains here that TFoo<T> is not yet completely defined. If I introduce an alias it does not work either, but if I subclass from TFooInteger and extend that class it does work (maybe the declaration of TFooInteger is treated like an alias in Delphi?). In FPC the above example currently compiles (there was no change needed for that). While I might file a bug report at Embarcadero, I'd like to know what your opinion regarding the correct behavior is.
I think this is a bug in XE.
3. Virtual methods and class helpers are another topic where a question is left. For correctly checking "override", etc. for helpers in mode Delphi I'm leaving the flags for virtual, etc. in the procdef although they should be ignored at the end. But the compiler checks them in some parts to do some special things for virtual methods (VMT, debug information, special code generation in the backends). The first two are solved rather easy, but should I introduce a check for helpers in the backends (calling "is_objectpascal_helper" for the owner of the procdef of the symbol) or should I introduce a "ignorevirtual" flag? I personally don't want the special virtual code to be generated for class helper methods, because it's unnecessary.
Don't generate it for class helpers using "is_objectpascal_helper".
4. The syntax that was introduced by Borland is not very pascalish in my opinion. So I'd like to change the syntax for mode ObjFPC a bit (sadly this won't simplify the parser anymore because of the Delphi compatibility). Delphi syntax: TypeIdentifier = class|record helper(ParentHelper) for ExtendedType Proposed FPC syntax: TypeIdentifier = helper(ParentHelper) for class|record ExtendedType What do you think? Maybe also the "class|record" part can be left out, because this part is not saved in the objectdef and can be determined by the compiler automatically.
I always think that if there is no need to create an incompatibility - better to not create it. But my ideas often does not get support of other FPC developers.
If you completed the class helpers syntax - then maybe to merge them into the trunk? Record helpers can be merged independently.
Best regards, Paul Ishenin _______________________________________________ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-devel
