(Hit a wrong button. Resending to the mailing list.)

> The primary question is how those relevant properties can be determined. For standard
> generators such as compilers it would be reasonable to look at all 'flags'
> settings for the corresponding rules and see which properties are in use there.

Are there any non-standard generators that do not use 'flags'? If there are it still should be possible to convert all standard generators but keep compatibility no filtering mode for others. I think the main problem would be the bugs in existing build scripts exposed by changes in the behavior of the standard generators.


> Also, there should be a mechanism to mark a specific feature as relevant or
> irrelevant for specific generator, or for specific metatarget (*).

There is a way to call a rule via "<conditional>@my-rule". We can define similar "<filter>@my-rule" feature to do the job. BTW can we use "<conditional>" to remove properties inherited from a parent?

I think starting with "<filter>" syntax is a better idea. It is not as intrusive as changing all generators. Once the concept proves itself we will be able to apply more radical changes to the generators.

--
Best regards,
 Alexey Pakhunov.