1 ///////////////////////////////////////////////////////////////////////////////
2 // cpp-next_bug.hpp
3 //
4 // Copyright 2012 Eric Niebler. Distributed under the Boost
5 // Software License, Version 1.0. (See accompanying file
6 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7
8 #include <vector>
9 #include <boost/proto/proto.hpp>
10 #include <boost/test/unit_test.hpp>
11 namespace mpl = boost::mpl;
12 namespace proto = boost::proto;
13 using proto::_;
14
15 namespace linear_algebra
16 {
17 // A trait that returns true only for std::vector
18 template<typename T>
19 struct is_std_vector
20 : mpl::false_
21 {};
22
23 template<typename T, typename A>
24 struct is_std_vector<std::vector<T, A> >
25 : mpl::true_
26 {};
27
28 // A type used as a domain for linear algebra expressions
29 struct linear_algebra_domain
30 : proto::domain<>
31 {};
32
33 // Define all the operator overloads for combining std::vectors
34 BOOST_PROTO_DEFINE_OPERATORS(is_std_vector, linear_algebra_domain)
35
36 // Take any expression and turn each node
37 // into a subscript expression, using the
38 // state as the RHS.
39 struct Distribute
40 : proto::or_<
41 proto::when<proto::terminal<_>, proto::_make_subscript(_, proto::_state)>
42 , proto::plus<Distribute, Distribute>
43 >
44 {};
45
46 struct Optimize
47 : proto::or_<
48 proto::when<
49 proto::subscript<Distribute, proto::terminal<_> >,
50 Distribute(proto::_left, proto::_right)
51 >
52 , proto::plus<Optimize, Optimize>
53 , proto::terminal<_>
54 >
55 {};
56 }
57
58 static const int celems = 4;
59 static int const value[celems] = {1,2,3,4};
60 std::vector<int> A(value, value+celems), B(A);
61
test1()62 void test1()
63 {
64 using namespace linear_algebra;
65 proto::_default<> eval;
66 BOOST_CHECK_EQUAL(8, eval(Optimize()((A + B)[3])));
67 }
68
69 using namespace boost::unit_test;
70 ///////////////////////////////////////////////////////////////////////////////
71 // init_unit_test_suite
72 //
init_unit_test_suite(int argc,char * argv[])73 test_suite* init_unit_test_suite( int argc, char* argv[] )
74 {
75 test_suite *test = BOOST_TEST_SUITE("test for a problem reported on the cpp-next.com blog");
76
77 test->add(BOOST_TEST_CASE(&test1));
78
79 return test;
80 }
81