[boost] [Modularization] Variant -> Math and the Serialization issue

Subject: [boost] [Modularization] Variant -> Math and the Serialization issue
From: Stephen Kelly (hello_at_[hidden])
Date: 2014-06-15 15:25:20

Hello,

In regard to the other thread on the subject, I take the position that it 
should not be a problem for a module to depend on the serialization module. 
I also take the position that there should not be an explosion of 
'serialization foo' modules.

That is why I propose reducing the dependencies of serialization, so that 
depending on serialization is not a problem. That is why I suggested 
removing the dependency 

 serialization -> spirit

The improvement resulting from that is shown here:

 http://www.steveire.com/boost/deps-june-14/serialization.png
 http://www.steveire.com/boost/after-edge-removal-june-14/serialization.png

So, now we need to remove the dependencies of the second graph. I draw your 
attention to the following dependencies:

 serialization ->variant
 variant -> math
 math -> [lots of stuff]

If the variant -> math edge is removed, we get this:

 http://www.steveire.com/boost/june-15-serialization-no-variant-math.png
 http://www.steveire.com/boost/june-15-serialization-no-variant-math.dot

which is already a significant improvement. There may be more low hanging 
fruit remaining.

Variant depends on math for a single metafunction.

 boost::math::static_lcm
 
Can something be changed to make Variant not depend on Math?

Thanks,

Steve.