From: dave@boostpro.com   
      
   on Fri Jun 08 2012, Seungbeom Kim  wrote:   
      
   > On 2012-06-07 12:02, Dave Abrahams wrote:   
   >> on Wed Jun 06 2012, "Martin B." <0xCDCDCDCD-AT-gmx.at> wrote:   
   >>>   
   >>> Mathias, Dave - I fail to see how an algorithm could help. I really   
   >>> don't get it.   
   >>>   
   >>> Can you provide an example where an algorithm based solution avoids   
   >>> the inefficiencies associated with declaring the temporary complex   
   >>> object inside the loop body?   
   >>   
   >> The implementor of the algorithm simply avoids declaring temporary   
   >> objects in his loops.  The algorithm implementor is not (or should   
   >> not be) subject to your guideline.  In fact, the guideline should   
   >> probably be rewritten in the form, "avoid doing XXX, or if you must,   
   >> encapsulate it."  That's pretty much the right form for most things   
   >> one might want to generally prohibit, like casts.   
   >   
   > What does an algorithm change with regard to the lifetime of   
   > temporaries?  Naturally, the functor may declare its own local   
   > variable in the scope of the function to be called, or it may try to   
   > use a variable that's supplied externally to the functor. In either   
   > case, I don't see any fundamental differences from the situations with   
   > the manually-written loops.   
      
   The algorithm implementor creates whatever temporaries she wants,   
   wherever she wants them.  The user of the algorithm can then stick to   
   the guideline.  Does that help explain?   
      
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   Dave Abrahams   
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