On 02/19/2018 11:38 AM, Michał Górny wrote:
> W dniu pon, 19.02.2018 o godzinie 21∶32 +0200, użytkownik Mart Raudsepp
> napisał:
>> On Mon, 2018-02-19 at 18:34 +0100, Ulrich Mueller wrote:
>>>>>>>> On Mon, 19 Feb 2018, Michael Lienhardt wrote:
>>>>>
>>>>> 2. ||= (binding any-of) dep groups.
>>>>
>>>> I don't understand what this group means, and the PMS-7 is unclear
>>>> as well:
>>>>   "binding-any-of A binding-any-of group, which has the same format
>>>>   as the any-of group, but begins with the string ||= instead."
>>>> Is it a "or", like the "any-of" group, but with a different
>>>> behavior
>>>> at compiling/linking time?
>>>
>>> It is explained in section 8.2.4:
>>> https://dev.gentoo.org/~ulm/pms/7-draft/pms.html#x1-800008.2.4
>>
>> Maybe I missed this, but a real world use case example would be nice,
>> maybe someone feels a harder itch to scratch then :)
>>
> 
> The original use case was for providers-like thingies, e.g.:
> 
>   ||= ( ffmpeg:0= libav:0= )
> 
> That said, I'd personally prefer doing that with proper USE_EXPAND
> and REQUIRED_USE enforcing but this has been rejected.

Indeed, the tendency of || deps to make things less deterministic can be
troublesome. Maybe automatic REQUIRED_USE satisfaction will make the
REQUIRED_USE approach more acceptable to those who have rejected it.
-- 
Thanks,
Zac