Re: [boost] [modularization] spirtit -> serialization

Subject: Re: [boost] [modularization] spirtit -> serialization
From: Peter Dimov (lists_at_[hidden])
Date: 2014-06-15 08:13:55

John Maddock wrote:
> IMO we need a better way of looking at dependencies, perhaps by marking up 
> glue headers as optional.

This approach causes difficulties down the road.

module X
    X.hpp

module Y
    Y1.hpp
    Y2.hpp (optional) includes X.hpp

module Z
    Z.hpp includes Y2.hpp

Does Z depend, indirectly, on X? If your answer is yes, and it must be, 
remember that Y does not depend on X, so the secondary dependencies are no 
longer the transitive closure of the primary dependencies.

The tool can be made to figure these things out, but to do so, it will need 
to create virtual submodules, one per each optional header.

Either that, or scrap the whole module-level dependency approach and start 
tracking individual headers.