From: pasa@lib.hu   
      
   On 12/2/2012 4:04 AM, Dave Abrahams wrote:   
   > Please, everyone, before arguing for Singleton,   
      
   In most singleton threads I sad in the last decade arguments were put   
   not FOR singleton, but AGAINST singleton-bashing.   
      
   > take some time to   
   > research the arguments against it and understand how Dependency   
   > Injection addresses those issues.   
      
   Honestly I didn't see the actual problems of singletons actually listed   
   in those DI-proponent articles, let alone address them. In a general   
   sense at least.   
      
   PFA, and singleton both have pros and cons, that we programmers should   
   match against the actual situation and go with the better. Or refactor   
   the system.   
      
   As for DI, that looks like a new branch in PFA I personally see it way   
   more poisonous than the singleton approach, and would not be surprised   
   at all if 10 years ahead we saw more DI-bashing threads than singleton   
   bashing today.   
      
   As sure, widening the global state is not good -- but if it's easy to   
   locate the *few* spots interested in the part really, it may be mitigated.   
      
   argument-based PFA blurs that possiblity, and DI does even worse, it   
   widens the object's state, for many objects. It makes actual usage less   
   visible rather than more visible as claimed.   And another side effect   
   that it has tendency to create over-engineered solutions.   And way more   
   overengineered ones than Singletons::MySingleton::GetTheInstance() crap.   
      
   I did experience so much bloat following those bashing threads, for most   
   everyday topics, assignment to flags replacing break, 8-level nested ifs   
   replacing an early guard-clause return, pasted code-blocks replacing   
   goto CLEANUP (in C); tons of getter/setters replacing public data in   
   structs equivalent to std::tuple, and many others.   
      
   Yes, globals and singletons CAN be bad for many reasons. But in many   
   situations those reasons don't apply at all.   
      
   But experience shows that due to general bashing many people will stop   
   evaluating reasons, just jump to use the strongly and emotionally   
   suggested alternative.  Creating a worse system and way more work to   
   those who actually understand SW engineering.   
      
      
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