Chris@16: #if !defined(BOOST_PROTO_DONT_USE_PREPROCESSED_FILES)
Chris@16: 
Chris@16:     #include <boost/proto/transform/detail/preprocessed/when.hpp>
Chris@16: 
Chris@16: #elif !defined(BOOST_PP_IS_ITERATING)
Chris@16: 
Chris@16:     #if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
Chris@16:         #pragma wave option(preserve: 2, line: 0, output: "preprocessed/when.hpp")
Chris@16:     #endif
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////////
Chris@16:     /// \file when.hpp
Chris@16:     /// Definition of when transform.
Chris@16:     //
Chris@16:     //  Copyright 2008 Eric Niebler. Distributed under the Boost
Chris@16:     //  Software License, Version 1.0. (See accompanying file
Chris@16:     //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16:     #if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
Chris@16:         #pragma wave option(preserve: 1)
Chris@16:     #endif
Chris@16: 
Chris@16:     #define BOOST_PP_ITERATION_PARAMS_1                                                             \
Chris@16:         (3, (0, BOOST_PROTO_MAX_ARITY, <boost/proto/transform/detail/when.hpp>))
Chris@16:     #include BOOST_PP_ITERATE()
Chris@16: 
Chris@16:     #if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
Chris@16:         #pragma wave option(output: null)
Chris@16:     #endif
Chris@16: 
Chris@16: #else
Chris@16: 
Chris@16:     #define N BOOST_PP_ITERATION()
Chris@16: 
Chris@16:     /// \brief A grammar element and a PrimitiveTransform that associates
Chris@16:     /// a transform with the grammar.
Chris@16:     ///
Chris@16:     /// Use <tt>when\<\></tt> to override a grammar's default transform
Chris@16:     /// with a custom transform. It is for used when composing larger
Chris@16:     /// transforms by associating smaller transforms with individual
Chris@16:     /// rules in your grammar, as in the following transform which
Chris@16:     /// counts the number of terminals in an expression.
Chris@16:     ///
Chris@16:     /// \code
Chris@16:     /// // Count the terminals in an expression tree.
Chris@16:     /// // Must be invoked with initial state == mpl::int_<0>().
Chris@16:     /// struct CountLeaves
Chris@16:     ///   : or_<
Chris@16:     ///         when<terminal<_>, mpl::next<_state>()>
Chris@16:     ///       , otherwise<fold<_, _state, CountLeaves> >
Chris@16:     ///     >
Chris@16:     /// {};
Chris@16:     /// \endcode
Chris@16:     ///
Chris@16:     /// The <tt>when\<G, R(A0,A1,...)\></tt> form accepts either a
Chris@16:     /// CallableTransform or an ObjectTransform as its second parameter.
Chris@16:     /// <tt>when\<\></tt> uses <tt>is_callable\<R\>::value</tt> to
Chris@16:     /// distinguish between the two, and uses <tt>call\<\></tt> to
Chris@16:     /// evaluate CallableTransforms and <tt>make\<\></tt> to evaluate
Chris@16:     /// ObjectTransforms.
Chris@16:     template<typename Grammar, typename R BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)>
Chris@16:     struct when<Grammar, R(BOOST_PP_ENUM_PARAMS(N, A))>
Chris@16:       : detail::when_impl<Grammar, R, R(BOOST_PP_ENUM_PARAMS(N, A))>
Chris@16:     {};
Chris@16: 
Chris@16:     #if N > 0
Chris@16:     /// \brief A grammar element and a PrimitiveTransform that associates
Chris@16:     /// a transform with the grammar.
Chris@16:     ///
Chris@16:     /// Use <tt>when\<\></tt> to override a grammar's default transform
Chris@16:     /// with a custom transform. It is for used when composing larger
Chris@16:     /// transforms by associating smaller transforms with individual
Chris@16:     /// rules in your grammar, as in the following transform which
Chris@16:     /// counts the number of terminals in an expression.
Chris@16:     ///
Chris@16:     /// \code
Chris@16:     /// // Count the terminals in an expression tree.
Chris@16:     /// // Must be invoked with initial state == mpl::int_<0>().
Chris@16:     /// struct CountLeaves
Chris@16:     ///   : or_<
Chris@16:     ///         when<terminal<_>, mpl::next<_state>()>
Chris@16:     ///       , otherwise<fold<_, _state, CountLeaves> >
Chris@16:     ///     >
Chris@16:     /// {};
Chris@16:     /// \endcode
Chris@16:     ///
Chris@16:     /// The <tt>when\<G, R(A0,A1,...)\></tt> form accepts either a
Chris@16:     /// CallableTransform or an ObjectTransform as its second parameter.
Chris@16:     /// <tt>when\<\></tt> uses <tt>is_callable\<R\>::value</tt> to
Chris@16:     /// distinguish between the two, and uses <tt>call\<\></tt> to
Chris@16:     /// evaluate CallableTransforms and <tt>make\<\></tt> to evaluate
Chris@16:     /// ObjectTransforms.
Chris@16:     template<typename Grammar, typename R BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)>
Chris@16:     struct when<Grammar, R(BOOST_PP_ENUM_PARAMS(N, A)...)>
Chris@16:       : detail::when_impl<Grammar, R, R(BOOST_PP_ENUM_PARAMS(N, A)...)>
Chris@16:     {};
Chris@16:     #endif
Chris@16: 
Chris@16:     #undef N
Chris@16: 
Chris@16: #endif