Subject: Re: [boost] New dependency report
From: Stephen Kelly (hello_at_[hidden])
Date: 2014-06-09 01:12:42
Ion Gaztañaga wrote:
> El 09/06/2014 0:24, Andrey Semashev escribió:
>> On Sunday 08 June 2014 23:53:41 Ion Gaztañaga wrote:
>>>
>>> TypeTraits would not be MPL
>>> dependant. MPL could depend on TypeTraits and Core.
>>
>> mpl::bool_ is not the only thing TypeTraits uses from MPL, so this
>> dependency won't go that easily. This is arguably true for other
>> libraries as well. Pulling more things from MPL to Core will make it
>> heavier. I'd like to keep MPL stuff localized and IMHO Core is not the
>> right place for it.
>
> Sorry, I missed the rest of dependencies. The circular dependency
> between MPL and TypeTraits doesn't sound very good from a a design point
> of view.
If separate modules are so tightly coupled that they are inseparable, they
are "incidentally" a single module (think 'incidental data structures').
Neither can exist without the other. Typeof and Core also participate in a
closed dependency loop with MPL and TypeTraits. The four form one
'incidental module'.
You could decide whether absence of incidental modules is a design goal. If
it is, then you can merge those four together when it is no longer possible
to remove edges between them.
Thanks,
Steve.