From: dave@boostpro.com   
      
   on Mon Dec 17 2012, Ian Collins  wrote:   
      
   > Dave Abrahams wrote:   
   >> on Sun Dec 16 2012, Dave Abrahams  wrote:   
   >>   
   >>> on Sat Dec 15 2012, Ian Collins  wrote:   
   >>>   
   >>>> One question regarding DI, how does it fit with overloaded   
   >>>> operators that use (in our case) a singleton internally?   
   >>>   
   >>> I'm afraid I don't know.  I think I understand the problem you're   
   >>> describing, and I don't see any easy way to avoid global state in   
   >>> that case.   
   >>   
   >> Oh, actually I do know.  You can inject dependencies via template   
   >> parameters without actually making them stateful (c.f. Allocators).   
   >> DI doesn't always have to happen at runtime.  Genericity can be very   
   >> good for testability, among other things.   
   >   
   > Maybe, but I can't see many projects accepting making classes   
   > templates just to avoid the use of a singleton.   
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^   
      
   Of course you can't, since most projects don't have avoiding singletons   
   as a primary goal.  They may, however, have flexibility, reusability,   
   testability, and/or generality as primary goals.  One way to achieve   
   those goals may be to make some classes into templates.  Being able to   
   avoid a singleton is merely one manifestation of those goals.   
      
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