Boost , The Boost C++ Libraries BoostBook Documentation Subset , Struct template when<Grammar, R(A...)>

Boost C++ Libraries

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Struct template impl

boost::proto::when<Grammar, R(A...)>::impl

Synopsis

// In header: <boost/proto/transform/when.hpp>

template<typename Expr, typename State, typename Data> 
struct impl :  proto::transform_impl< Expr, State, Data > {
  // types
  typedef proto::call<R(A...)>                                       call_;        // For exposition only
  typedef proto::make<R(A...)>                                       make_;        // For exposition only
  typedef typename mpl::if_<proto::is_callable<R>,call_,make_>::type which;        // For exposition only
  typedef typename boost::result_of<which(Expr, State, Data)>::type  result_type;
  // public member functions
  result_type operator()(typename impl::expr_param, 
                         typename impl::state_param, 
                         typename impl::data_param) const;
};

Description

`impl` public member functions

<
```
result_typeoperator()(typenameimpl::expr_paramexpr,
                      typenameimpl::state_paramstate,
                      typenameimpl::data_paramdata)const;
```
>
Оценить<R(A...)>как преобразование либо с<proto::call<>>, либо с<proto::make<>>в зависимости от того,<proto::is_callable>:: значениеявляется<true>или<false>.
Параметры:
<data>
[ [
[ [ [
[ [
[
Произвольные данные
<expr>
Текущее выражение
<state>
Нынешнее состояние

Struct template impl

Boost , The Boost C++ Libraries BoostBook Documentation Subset , Struct template when<Grammar, R(A...)>

Boost C++ Libraries

Struct template impl

Synopsis

Description

impl public member functions

`impl` public member functions