1#if !defined(BOOST_PROTO_DONT_USE_PREPROCESSED_FILES)
2
3 #include <boost/proto/transform/detail/preprocessed/lazy.hpp>
4
5#elif !defined(BOOST_PP_IS_ITERATING)
6
7 #if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
8 #pragma wave option(preserve: 2, line: 0, output: "preprocessed/lazy.hpp")
9 #endif
10
11 ///////////////////////////////////////////////////////////////////////////////
12 /// \file lazy.hpp
13 /// Contains definition of the lazy<> transform.
14 //
15 // Copyright 2008 Eric Niebler. Distributed under the Boost
16 // Software License, Version 1.0. (See accompanying file
17 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
18
19 #if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
20 #pragma wave option(preserve: 1)
21 #endif
22
23 #define BOOST_PP_ITERATION_PARAMS_1 \
24 (3, (0, BOOST_PROTO_MAX_ARITY, <boost/proto/transform/detail/lazy.hpp>))
25 #include BOOST_PP_ITERATE()
26
27 #if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
28 #pragma wave option(output: null)
29 #endif
30
31#else
32
33 #define N BOOST_PP_ITERATION()
34
35 /// \brief A PrimitiveTransform that uses <tt>make\<\></tt> to build
36 /// a CallableTransform, and then uses <tt>call\<\></tt> to apply it.
37 ///
38 /// <tt>lazy\<\></tt> is useful as a higher-order transform, when the
39 /// transform to be applied depends on the current state of the
40 /// transformation. The invocation of the <tt>make\<\></tt> transform
41 /// evaluates any nested transforms, and the resulting type is treated
42 /// as a CallableTransform, which is evaluated with <tt>call\<\></tt>.
43 template<typename Object BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)>
44 struct lazy<Object(BOOST_PP_ENUM_PARAMS(N, A))>
45 : transform<lazy<Object(BOOST_PP_ENUM_PARAMS(N, A))> >
46 {
47 template<typename Expr, typename State, typename Data>
48 struct impl
49 : call<
50 typename make<Object>::template impl<Expr, State, Data>::result_type
51 (BOOST_PP_ENUM_PARAMS(N, A))
52 >::template impl<Expr, State, Data>
53 {};
54 };
55
56 #if N > 0
57 template<typename Object BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)>
58 struct lazy<Object(BOOST_PP_ENUM_PARAMS(N, A)...)>
59 : transform<lazy<Object(BOOST_PP_ENUM_PARAMS(N, A)...)> >
60 {
61 template<typename Expr, typename State, typename Data>
62 struct impl
63 : lazy<
64 typename detail::expand_pattern<
65 proto::arity_of<Expr>::value
66 , BOOST_PP_CAT(A, BOOST_PP_DEC(N))
67 , detail::BOOST_PP_CAT(expand_pattern_rest_, BOOST_PP_DEC(N))<
68 Object
69 BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_DEC(N), A)
70 >
71 >::type
72 >::template impl<Expr, State, Data>
73 {};
74 };
75 #endif
76
77 #undef N
78
79#endif
80