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   comp.lang.c++.moderated      Moderated discussion of C++ superhackery      33,346 messages   

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   Message 31,404 of 33,346   
   =?ISO-8859-1?Q?Daniel_Kr=FCgler?= to All   
   Re: any_of, all_of, none_of   
   25 Aug 11 05:26:42   
   
   a1a5d93d   
   From: daniel.kruegler@googlemail.com   
      
   Am 24.08.2011 03:49, schrieb gast128@hotmail.com:   
   > Hello all,   
   >   
   > I was wondering why the c++ committee didn't decide to stick to the   
   > '_if' convention as used in other STL algorithm, like all/all_if,   
   > any / any_if etc.   
      
   In principle that would have been possible, but the request of   
   any/all/none is already so fundamental, that the absence of an explicit   
   customization point (the predicate) makes a further reduction hard to   
   argue for.   
      
   > These new algorithms seems only be defined for use with predicates.   
   > But what if u just want to use these for testing against a value, you   
   > now have to bind an argument to an equal_to structure. Or perhaps this   
   > can be easier done?   
   >   
   > void f()   
   > {   
   >      std::vector  vec(1, 3);   
   >   
   >      const bool bAny = std::any_of(vec.begin(), vec.end(),   
   > boost::bind(std::equal_to(), _1, 3));   
   >      _ASSERT(bAny);   
   > }   
      
   Just use a lambda expression instead:   
      
   void f()   
   {   
        std::vector vec(1, 3);   
      
        const bool bAny = std::any_of(vec.begin(), vec.end(),   
         [](int value) { return value == 3; });   
        _ASSERT(bAny);   
   }   
      
   HTH & Greetings from Bremen,   
      
   Daniel Krügler   
      
      
      
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