FunctorTraits< T > Class Template Reference

Export associated information for a functor. More...

#include <vigra/functortraits.hxx>

Inherits FunctorTraitsBase< T >.

Detailed Description

template<class T>
class vigra::FunctorTraits< T >

Export associated information for a functor.

The FunctorTraits class contains the following fields:

template <class T>
struct FunctorTraits
{
    typedef T type;
    
    typedef ... isInitializer;

    typedef ... isUnaryFunctor;
    typedef ... isBinaryFunctor;
    typedef ... isTernaryFunctor;
    
    typedef ... isUnaryAnalyser;
    typedef ... isBinaryAnalyser;
    typedef ... isTernaryAnalyser;
};

where the dots are either VigraTrueType or VigraFalseType depending on whether the functor supports the respective functionality or not. Note that these traits are automatically defined correctly when your functor is derived from the appropriate functor tag classes:

struct InitializerTag {};
struct UnaryFunctorTag {};
struct BinaryFunctorTag {};
struct TernaryFunctorTag {};
struct UnaryAnalyserTag {};
struct BinaryAnalyserTag {};
struct TernaryAnalyserTag {};
struct UnaryReduceFunctorTag : public InitializerTag, public UnaryAnalyserTag {};
struct BinaryReduceFunctorTag : public InitializerTag, public BinaryAnalyserTag {};

If a functor f is a model of these categories, it supports the following calls (v is a variable such that the result type of the functor calls can be converted into v's type, and a1, a2, a3 are variables convertible into the functor's argument types):

Initializer

v = f() (used with initImageWithFunctor())

UnaryFunctor

v = f(a1) (used with transformImage())

BinaryFunctor

v = f(a1, a2) (used with combineTwoImages())

TernaryFunctor

v = f(a1, a2, a3) (used with combineThreeImages())

UnaryAnalyser

f(a1) (return type void, used with inspectImage())

BinaryAnalyser

f(a1, a2) (return type void, used with inspectTwoImages())

TernaryAnalyser

f(a1, a2, a3) (return type void)

It should be noted that the functor's argument and result types are not contained in the traits class: Since the function calls are often member template functions in VIGRA, many functors do not have fixed argument types. Neither are the result types fixed in this case because they are computed (via a template meta-program) from the argument types.

#include <vigra/functortraits.hxx>
Namespace: vigra

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The documentation for this class was generated from the following file:

• vigra/functortraits.hxx