1 /*=============================================================================
2 Phoenix V1.2.1
3 Copyright (c) 2001-2003 Joel de Guzman
4
5 Use, modification and distribution is subject to the Boost Software
6 License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
7 http://www.boost.org/LICENSE_1_0.txt)
8 ==============================================================================*/
9 #include <vector>
10 #include <algorithm>
11 #include <iostream>
12 #include <boost/spirit/include/phoenix1_operators.hpp>
13 #include <boost/spirit/include/phoenix1_primitives.hpp>
14 #include <boost/spirit/include/phoenix1_composite.hpp>
15 #include <boost/spirit/include/phoenix1_special_ops.hpp>
16
17 using namespace std;
18 using namespace phoenix;
19
20 //////////////////////////////////
21 template <typename CondT, typename TrueT, typename FalseT>
22 struct if_else_composite {
23
24 typedef if_else_composite<CondT, TrueT, FalseT> self_t;
25
26 template <typename TupleT>
27 struct result {
28
29 typedef typename higher_rank<
30 typename actor_result<TrueT, TupleT>::plain_type,
31 typename actor_result<FalseT, TupleT>::plain_type
32 >::type type;
33 };
34
if_else_compositeif_else_composite35 if_else_composite(
36 CondT const& cond_, TrueT const& true__, FalseT const& false__)
37 : cond(cond_), true_(true__), false_(false__) {}
38
39 template <typename TupleT>
40 typename actor_result<self_t, TupleT>::type
evalif_else_composite41 eval(TupleT const& args) const
42 {
43 return cond.eval(args) ? true_.eval(args) : false_.eval(args);
44 }
45
46 CondT cond; TrueT true_; FalseT false_; // actors
47 };
48
49 //////////////////////////////////
50 template <typename CondT, typename TrueT, typename FalseT>
51 inline actor<if_else_composite<
52 typename as_actor<CondT>::type,
53 typename as_actor<TrueT>::type,
54 typename as_actor<FalseT>::type> >
if_else_(CondT const & cond,TrueT const & true_,FalseT const & false_)55 if_else_(CondT const& cond, TrueT const& true_, FalseT const& false_)
56 {
57 typedef if_else_composite<
58 typename as_actor<CondT>::type,
59 typename as_actor<TrueT>::type,
60 typename as_actor<FalseT>::type>
61 result;
62
63 return result(
64 as_actor<CondT>::convert(cond),
65 as_actor<TrueT>::convert(true_),
66 as_actor<FalseT>::convert(false_));
67 }
68
69 //////////////////////////////////
70 int
main()71 main()
72 {
73 int init[] = { 2, 10, 4, 5, 1, 6, 8, 3, 9, 7 };
74 vector<int> c(init, init + 10);
75 typedef vector<int>::iterator iterator;
76
77 // Print all contents of an stl container c and
78 // prefix " is odd" or " is even" appropriately.
79
80 for_each(c.begin(), c.end(),
81 cout
82 << arg1
83 << if_else_(arg1 % 2 == 1, " is odd", " is even")
84 << val('\n')
85 );
86
87 return 0;
88 }
89