boost::proto::otherwise< Fun > Struct Template Reference

Syntactic sugar for when<_, Fun>, for use in grammars to handle all the cases not yet handled. More...

#include <when.hpp>

Inheritance diagram for boost::proto::otherwise< Fun >:

Collaboration diagram for boost::proto::otherwise< Fun >:

Public Types
typedef _	first
typedef Fun	second
typedef _::proto_grammar	proto_grammar

Detailed Description

template<typename Fun>
struct boost::proto::otherwise< Fun >

Syntactic sugar for when<_, Fun>, for use in grammars to handle all the cases not yet handled.

Use otherwise<T> in your grammars as a synonym for when<_, T> as in the following transform which counts the number of terminals in an expression.

// Count the terminals in an expression tree.
// Must be invoked with initial state == mpl::int_<0>().
struct CountLeaves
  : or_<
        when<terminal<_>, mpl::next<_state>()>
      , otherwise<fold<_, _state, CountLeaves> >
    >
{};

Member Typedef Documentation

typedef _ boost::proto::when< _ , Fun >::first

inherited

typedef _ ::proto_grammar boost::proto::when< _ , Fun >::proto_grammar

inherited

typedef Fun boost::proto::when< _ , Fun >::second

inherited

---

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

• boost_1_57_0/boost/proto/proto_fwd.hpp