John Torjo <john.groups <at> torjo.com> writes:
Today starts the formal Fast-Track review of the Boost.Utility/Singleton library. This is a very useful utility, so I'm expecting lots of reviews ;)
* What is your evaluation of the potential usefulness of the library?
I don't think this is at all useful. People should not be encouraged to use singletons, as there is already a tendency towards overuse. In most circumstances, singletons are a poor design choice, so there is little requirement for their use.
* What is your evaluation of the design? * What is your evaluation of the implementation?
The design mixes several independent issues --- ensuring there is only one instance of a class and avoiding initialization order problems with on-demand initialization for starters. A simple wrapper class that allows for on-demand initialization, would be useful. Conflating that with "there shall be at most one instance" is not. Again, allowing for a preferred destruction sequence of objects with such on-demand initialization might also be useful, but does not belong with the one-instance constraint. thread_specific_singleton is overly complex for what should just amount to a simple use of thread_specific_ptr.
* Did you try to use the library? With what compiler? Did you have any problems?
No, I haven't tried to use it.
* How much effort did you put into your evaluation?
I've read through the code and documentation carefully.
* Are you knowledgeable about the problem domain?
Yes. I've written code that used singletons (and regretted it later), and used code that other people have written containing singletons.
* Do you think the library should be accepted as a Boost library?
No. Anthony