zypp::functor::functor_detail Namespace Reference

An unary functor forwarding to some other TFunctor &. More...

Classes
struct	FunctorRef0
struct	FunctorRef1
struct	FunctorRef2
struct	nil

Detailed Description

An unary functor forwarding to some other TFunctor &.

Most algorithms take functor arguments by value. That's inconvenient if the functor wants to collect and return data. Creating and passing a FunctorRef to the algorithm, may help you out of this.

// Counts invokations of operator().
template<class Tp>
  struct Counter : public std::unary_function<Tp, void>
  {
    void operator()( Tp )
    { ++_value; }

    Counter() : _value( 0 ) {}

    unsigned _value;
  };

std::set<SomeType> c;
Counter<SomeType> counter;
// Invokations of FunctorRef are forwarded to counter:
std::for_each( c.begin, c.end(),
               // currently you must specify the
               // operator() signature:
               functorRef<void,SomeType>(counter)
             );

Note

FunctorRef must be able to deduce the signature of TFunctor::operator(). This is currently not automated, so you must specify the operator() signature as template arguments.

The order is <result_type, arg1_type, ...> (this differs from std::, where the result comes last).

Todo:

drop it an use boost::ref