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