Re: [boost] Radical idea for repository structure

From: Beman Dawes (bdawes_at_[hidden])
Date: 2007-09-17 21:39:12

David Abrahams wrote:
> A few days ago I started thinking about the implications of giving
> each Boost library a separate subtree of the repository, and it led me
> to some interesting places.
> 
> * Start with the assumption that each library has a boost/ directory
>   containing its subset of the headers it currently has.  So, for
>   example, Boost.Python would have
> 
>            boost/
>               python.hpp
>               python/  
>                  ...
> 
>   where "..." above is identical to the current contents of
>   $BOOST_ROOT/boost/python/
> 
> * Our release process would merge the boost/ directories
> 
> * To test a library from a source distribution, you'd need to get the
>   boost/ directories of any libraries it depends on into the #include
>   path.
> 
> * This list of dependency libraries would be encoded in each dependent
>   library's Jamfile.
> 
> * Presto, a way to explicitly declare and track library
>   inter-dependencies!  If you fail to declare a dependency in your
>   Jamfile, your tests won't compile.
> 
> Thoughts?

Question 1: Does that mean different Jamfiles are needed for releases vs 
SVN working copies? That is too error prone - a way would have to be 
found so that the same Jamfile works regardless of whether it is run 
against a release or a SVN working copy.

Question 2: Let's say lib A depends on lib B, and B in turn depends on 
lib C. Does that mean lib A's Jamfile must list both B and C? If such 
transitive dependencies have to be listed, that's a problem because if C 
gets changed to depend on lib D, then the Jamfile for A, B, and C all 
have to be changed, and that's a mess. OTOH, if only direct dependencies 
have to be listed in the Jamfile, it might possibly work.

Question 3: What about developers who use an IDE or traditional make 
files? For example, using the VC++ IDE, the "Additional Include 
Directories" property is currently set to $(BOOST_ROOT) and you are 
done. On IDE's where this sort of property can be inherited, you only 
have to specify that in one place, and all Boost compiles work 
correctly. With your scheme it sounds like every library used will 
require an additional include path, and that path will be different for 
release compared to SVN working copies. That gets old fast. Or have you 
figured out a simpler way?

Curious,

--Beman