David Abrahams wrote:
on Mon Oct 26 2009, Joel de Guzman <joel-AT-boost-consulting.com> wrote:
FWIW, we've solved that by having a flat include directory. It's the include/ dir you see up there. The directory contains all forwarding headers. For instance, see http://tinyurl.com/yj86r8v. You have:
#include <boost/fusion/include/deref.hpp>
in addition to the modular:
#include <boost/fusion/iterator/deref.hpp>
Oh yeah, I forgot about that. Not bad, but the problem is... I tend to forget it. So I reach for boost/fusion/deref.hpp as though all libraries use that convention, and I am slowed down until I can remind myself that fusion is different. Consistency in these little things goes a long way toward ease-of-use.
It's always a balance. I advocate a clean modular structure as much as I advocate ease of use. I think the clean layout of Fusion is one of the reasons why people easily get what's going on and the barrier to contributing back to the code-base is lower. If one wants to understand iterators or sequences, they need to look at the headers in only one directory, not distributed all over the place. I also advocate consistency. That is why I chose that structure. It's not different at all, if you think in terms of modularity. Boost is a set of libraries; each library is composed of smaller sub-libraries or components, and so on. The (outermost) main boost goes like this: boost/ libx/ liby/ libx.hpp liby.hpp Some libraries, especially the bigger ones really ought to be broken down into sub-libraries or modules. Following the main header convention, it goes the same for sub-libraries, e.g.: boost/ libx/ modx/ mody/ modx.hpp mody.hpp liby/ libx.hpp liby.hpp You only have one consistent header policy (i.e sub-modules are no different than main modules). If you think about it in that regard, boost/fusion/deref.hpp is actually inconsistent. A header such as boost/libname/foo.hpp is only consistent if libname is monolithic (does not comprise of smaller modules or sub-libraries). IMHO, that is good only for small libraries. Regards, -- Joel de Guzman http://www.boostpro.com http://spirit.sf.net http://www.facebook.com/djowel Meet me at BoostCon http://www.boostcon.com/home http://www.facebook.com/boostcon