Boost C++ Libraries

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Struct template unpack_expr

boost::proto::functional::unpack_expr — A PolymorphicFunctionObject equivalent to the proto::unpack_expr() function.

Synopsis

// In header: <boost/proto/make_expr.hpp>

template<typename Tag, typename Domain = proto::deduce_domain> 
struct unpack_expr :  proto::callable {
  // member classes/structs/unions
  template<typename This, typename Sequence> 
  struct result<This(Sequence)> :  
    proto::result_of::unpack_expr<
      Tag,
      Domain,
      typename boost::remove_reference< Sequence >::type
    >
  {
  };

  // public member functions
  template<typename Sequence> 
    typename proto::result_of::unpack_expr< Tag, Domain, Sequence const >::type const 
    operator()(Sequence const &) const;
};

Description

In all cases, proto::functional::unpack_expr<Tag, Domain>()(seq) is equivalent to proto::unpack_expr()<Tag, Domain>(seq).

proto::functional::unpack_expr<Tag>()(seq) is equivalent to proto::unpack_expr()<Tag>(seq).

`unpack_expr` public member functions

```
template<typename Sequence> 
  typename proto::result_of::unpack_expr< Tag, Domain, Sequence const >::type const 
  operator()(Sequence const & sequence) const;
```
Construct an expression node with tag type Tag and in the domain Domain.

Parameters:

sequence

A Fusion Forward Sequence

Returns:

proto::unpack_expr<Tag, Domain>(sequence)