libsigc++ 2.4.1

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Classes | Functions
compose()
Adaptors

sigc::compose() combines two or three arbitrary functors. More...

## Classes
struct | sigc::compose1_functor< T_setter, T_getter >
| Adaptor that combines two functors. More...
struct | sigc::compose2_functor< T_setter, T_getter1, T_getter2 >
| Adaptor that combines three functors. More...

## Functions
template<class T_setter , class T_getter >
compose1_functor< T_setter, T_getter > | sigc::compose (const T_setter& _A_setter, const T_getter& _A_getter)
| Creates an adaptor of type sigc::compose1_functor which combines two functors. More...
template<class T_setter , class T_getter1 , class T_getter2 >
compose2_functor< T_setter, T_getter1, T_getter2 > | sigc::compose (const T_setter& _A_setter, const T_getter1& _A_getter1, const T_getter2& _A_getter2)
| Creates an adaptor of type sigc::compose2_functor which combines three functors. More...

## Detailed Description

sigc::compose() combines two or three arbitrary functors.

On invokation, parameters are passed on to one or two getter functor(s). The return value(s) are then passed on to the setter function.

Examples:
  float square_root(float a) { return sqrtf(a); }
  float sum(float a, float b) { return a+b; }
  std::cout << sigc::compose(&square_root, &sum)(9, 16); // calls square_root(sum(3,6))
  std::cout << sigc::compose(&sum, &square_root, &square_root)(9); // calls sum(square_root(9), square_root(9))

The functor sigc::compose() returns can be passed directly into sigc::signal::connect().

Example:
  sigc::signal<float,float,float> some_signal;
  some_signal.connect(sigc::compose(&square_root, &sum));

For a more powerful version of this functionality see the lambda library adaptor sigc::group() which can bind, hide and reorder arguments arbitrarily. Although sigc::group() is more flexible, sigc::bind() provides a means of binding parameters when the total number of parameters called is variable.

## Function Documentation

template <class T_setter , class T_getter >

compose1_functor<T_setter, T_getter> sigc::compose | ( | const T_setter & | _A_setter,
|  | const T_getter & | _A_getter
| ) |  |
| inline

Creates an adaptor of type sigc::compose1_functor which combines two functors.

Parameters

  _A_setter | Functor that receives the return value of the invokation of _A_getter.
  _A_getter | Functor to invoke from operator()().

Returns
  Adaptor that executes _A_setter with the value returned from invokation of _A_getter.

template <class T_setter , class T_getter1 , class T_getter2 >

compose2_functor<T_setter, T_getter1, T_getter2> sigc::compose | ( | const T_setter & | _A_setter,
|  | const T_getter1 & | _A_getter1,
|  | const T_getter2 & | _A_getter2
| ) |  |
| inline

Creates an adaptor of type sigc::compose2_functor which combines three functors.

Parameters

  _A_setter | Functor that receives the return values of the invokation of _A_getter1 and _A_getter2.
  _A_getter1 | Functor to invoke from operator()().
  _A_getter2 | Functor to invoke from operator()().

Returns
  Adaptor that executes _A_setter with the values return from invokation of _A_getter1 and _A_getter2.