Nat, thanks for your very positive review. Nat Goodspeed wrote:

John Torjo wrote:

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Today starts the formal Fast-Track review of the Boost.Utility/Singleton library.

What to include in Review Comments ==================================

Here are some questions you might want to answer in your review:

* What is your evaluation of the design?

Very strong. I like it! I've implemented CRTP Singleton templates a few times before -- highlighting the need for a Boost library. ;-) I'm pleased with the deluxe functionality:

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* What is your evaluation of the documentation?

Very clear, though not entirely complete, as described below. The organization and style is excellent, and when polished, this documentation will be exemplary. I like the examples. Pointing out the ability to bind() instance and/or lease, and the semantics of each, is great. Also the multiple-inheritance example to graft Singleton behavior onto an existing class. I didn't fully understand the thrust of the example described as: "We might as well have a static facility use the Singleton internally, by using non-public inheritance". A few more words about that example would be useful; maybe a bit of the implementation of static void message().

I might have kept it so brief since I'm not too sure it's good practice. I think I'll better just remove it.

It appears that the third template parameter SubsystemTag was a recent introduction. The documentation (especially the reference material) doesn't describe it enough, and often fails to mention it entirely.

Yes.

The first paragraph under http://torjo.com/tobias/index.html#boost_utility_singleton._singletons_and_d... seems to want to be a bullet list that got flowed instead.

Yes.

Very little is said about BOOST_SINGLETON_PLACEMENT and BOOST_SINGLETON_PLACEMENT_DECLARATION. The reference material mentions them without any explanation.

That "Singletons and dynamic libraries" section explains their purpose. What exactly is missing? I'm not too fond of specifying what those macros expand to and I don't really want to mention them in the introductory section either, as for me they are kind-of workarounds for the imperfect ABIs we have to deal with.

The example http://torjo.com/tobias/index.html#boost_utility_singleton._singletons_and_d... appears to be inconsistent: shouldn't mylib_tag and library_tag be the same, one way or the other?

They should. My head must had been on vacation revising the docs.

Also, that example combines three different mechanisms: BOOST_SINGLETON_PLACEMENT, destroy_singletons() and SubsystemTag. More explanation of the role of each (why are we using that mechanism here?), and how they interact -- or remain orthogonal -- would clarify.

Yes. Regards, Tobias