Ticket 10988 - Filtered adaptor should only require SinglePassRange.

doc/reference/adaptors/filtered.qbk

@@ -12,9 +12,9 @@
 ]
 
 * [*Precondition:]  The `value_type` of the range is convertible to the argument type of `pred`.
-* [*Postcondition:] For all adjacent elements `[x]` in the returned range, `pred(x)` is `true`.
+* [*Postcondition:] For all elements `[x]` in the returned range, `pred(x)` is `true`.
 * [*Throws:] Whatever the copy constructor of `pred` might throw.
-* [*Range Category:] __forward_range__
+* [*Range Category:] __singlepass_range__
 * [*Range Return Type:] `boost::filtered_range<decltype(rng)>`
 * [*Returned Range Category:] The minimum of the range category of `rng` and __bidirectional_range__
 

include/boost/range/adaptor/filtered.hpp

@@ -56,23 +56,23 @@ namespace boost
             { }
         };
 
-        template< class ForwardRange, class Predicate >
+        template< class SinglePassRange, class Predicate >
-        inline filtered_range<Predicate, ForwardRange>
+        inline filtered_range<Predicate, SinglePassRange>
-        operator|(ForwardRange& r,
+        operator|(SinglePassRange& r,
                   const filter_holder<Predicate>& f)
         {
-            BOOST_RANGE_CONCEPT_ASSERT((ForwardRangeConcept<ForwardRange>));
+            BOOST_RANGE_CONCEPT_ASSERT((SinglePassRangeConcept<SinglePassRange>));
-            return filtered_range<Predicate, ForwardRange>( f.val, r );
+            return filtered_range<Predicate, SinglePassRange>( f.val, r );
         }
 
-        template< class ForwardRange, class Predicate >
+        template< class SinglePassRange, class Predicate >
-        inline filtered_range<Predicate, const ForwardRange>
+        inline filtered_range<Predicate, const SinglePassRange>
-        operator|(const ForwardRange& r,
+        operator|(const SinglePassRange& r,
                   const filter_holder<Predicate>& f )
         {
             BOOST_RANGE_CONCEPT_ASSERT((
-                ForwardRangeConcept<const ForwardRange>));
+                SinglePassRangeConcept<const SinglePassRange>));
-            return filtered_range<Predicate, const ForwardRange>( f.val, r );
+            return filtered_range<Predicate, const SinglePassRange>( f.val, r );
         }
 
     } // 'range_detail'
@@ -93,23 +93,26 @@ namespace boost
                        range_detail::forwarder<range_detail::filter_holder>();
         }
 
-        template<class ForwardRange, class Predicate>
+        template<class SinglePassRange, class Predicate>
-        inline filtered_range<Predicate, ForwardRange>
+        inline filtered_range<Predicate, SinglePassRange>
-        filter(ForwardRange& rng, Predicate filter_pred)
+        filter(SinglePassRange& rng, Predicate filter_pred)
-        {
-            BOOST_RANGE_CONCEPT_ASSERT((ForwardRangeConcept<ForwardRange>));
-
-            return range_detail::filtered_range<Predicate, ForwardRange>( filter_pred, rng );
-        }
-
-        template<class ForwardRange, class Predicate>
-        inline filtered_range<Predicate, const ForwardRange>
-        filter(const ForwardRange& rng, Predicate filter_pred)
         {
             BOOST_RANGE_CONCEPT_ASSERT((
-                ForwardRangeConcept<const ForwardRange>));
+                SinglePassRangeConcept<SinglePassRange>));
 
-            return range_detail::filtered_range<Predicate, const ForwardRange>( filter_pred, rng );
+            return range_detail::filtered_range<
+                Predicate, SinglePassRange>( filter_pred, rng );
+        }
+
+        template<class SinglePassRange, class Predicate>
+        inline filtered_range<Predicate, const SinglePassRange>
+        filter(const SinglePassRange& rng, Predicate filter_pred)
+        {
+            BOOST_RANGE_CONCEPT_ASSERT((
+                SinglePassRangeConcept<const SinglePassRange>));
+
+            return range_detail::filtered_range<
+                Predicate, const SinglePassRange>( filter_pred, rng );
         }
     } // 'adaptors'
 

test/Jamfile.v2

@@ -40,10 +40,6 @@ test-suite range :
     [ compile-fail compile_fail/adaptor/copied_concept2.cpp ]
     [ compile-fail compile_fail/adaptor/copied_concept3.cpp ]
     [ compile-fail compile_fail/adaptor/copied_concept4.cpp ]
-    [ compile-fail compile_fail/adaptor/filtered_concept.cpp ]
-    [ compile-fail compile_fail/adaptor/filtered_concept2.cpp ]
-    [ compile-fail compile_fail/adaptor/filtered_concept3.cpp ]
-    [ compile-fail compile_fail/adaptor/filtered_concept4.cpp ]
     [ compile-fail compile_fail/adaptor/reversed_concept.cpp ]
     [ compile-fail compile_fail/adaptor/reversed_concept2.cpp ]
     [ compile-fail compile_fail/adaptor/reversed_concept3.cpp ]

test/adaptor_test/filtered.cpp

@@ -21,6 +21,7 @@
 #include <set>
 #include <string>
 #include <vector>
+#include <sstream>
 
 namespace boost
 {
@@ -113,12 +114,35 @@ namespace boost
             filtered_test_impl< Container, is_even >();
         }
 
+        void ticket_10988_single_pass()
+        {
+            std::vector<int> v;
+            std::string str("0 1 2 3 4 5");
+            std::istringstream in(str);
+
+            boost::push_back(v,
+                boost::make_iterator_range(
+                    std::istream_iterator<int>(in),
+                    std::istream_iterator<int>())
+                | boost::adaptors::filtered(is_even()));
+
+            std::vector<int> reference;
+            for (int i = 0; i < 6; i += 2)
+            {
+                reference.push_back(i);
+            }
+            BOOST_CHECK_EQUAL_COLLECTIONS(
+                reference.begin(), reference.end(),
+                v.begin(), v.end());
+        }
+
         void filtered_test()
         {
             filtered_test_all_predicates< std::vector< int > >();
             filtered_test_all_predicates< std::list< int > >();
             filtered_test_all_predicates< std::set< int > >();
             filtered_test_all_predicates< std::multiset< int > >();
+            ticket_10988_single_pass();
         }
     }
 }

test/compile_fail/adaptor/filtered_concept.cpp

@@ -1,38 +0,0 @@
-// Boost.Range library
-//
-// Copyright Neil Groves 2014. Use, modification and distribution is subject
-// to 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)
-//
-// For more information, see http://www.boost.org/libs/range
-//
-
-#include "mock_range.hpp"
-#include <boost/range/adaptor/filtered.hpp>
-
-namespace
-{
-
-struct always_true
-{
-    typedef bool result_type;
-
-    bool operator()(int) const
-    {
-        return true;
-    }
-};
-
-} // anonymous namespace
-
-int main(int, const char**)
-{
-    using boost::range::unit_test::mock_range;
-    using boost::adaptors::filtered;
-
-    // This next line should fail when Boost.Range concept checking is
-    // enabled since the filtered adaptor takes at least a ForwardRange.
-    return (mock_range<boost::single_pass_traversal_tag>() |
-                filtered(always_true())).front();
-}

test/compile_fail/adaptor/filtered_concept2.cpp

@@ -1,38 +0,0 @@
-// Boost.Range library
-//
-// Copyright Neil Groves 2014. Use, modification and distribution is subject
-// to 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)
-//
-// For more information, see http://www.boost.org/libs/range
-//
-
-#include "mock_range.hpp"
-#include <boost/range/adaptor/filtered.hpp>
-
-namespace
-{
-
-struct always_true
-{
-    typedef bool result_type;
-
-    bool operator()(int) const
-    {
-        return true;
-    }
-};
-
-} // anonymous namespace
-
-int main(int, const char**)
-{
-    using boost::range::unit_test::mock_const_range;
-    using boost::adaptors::filtered;
-
-    // This next line should fail when Boost.Range concept checking is
-    // enabled since the filtered adaptor takes at least a ForwardRange.
-    return (mock_const_range<boost::single_pass_traversal_tag>() |
-                filtered(always_true())).front();
-}

test/compile_fail/adaptor/filtered_concept3.cpp

@@ -1,38 +0,0 @@
-// Boost.Range library
-//
-// Copyright Neil Groves 2014. Use, modification and distribution is subject
-// to 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)
-//
-// For more information, see http://www.boost.org/libs/range
-//
-
-#include "mock_range.hpp"
-#include <boost/range/adaptor/filtered.hpp>
-
-namespace
-{
-
-struct always_true
-{
-    typedef bool result_type;
-
-    bool operator()(int) const
-    {
-        return true;
-    }
-};
-
-} // anonymous namespace
-
-int main(int, const char**)
-{
-    using boost::range::unit_test::mock_range;
-
-    // This next line should fail when Boost.Range concept checking is
-    // enabled since the filtered adaptor takes at least a ForwardRange.
-    return boost::adaptors::filter(
-        mock_range<boost::single_pass_traversal_tag>(),
-        always_true()).front();
-}

test/compile_fail/adaptor/filtered_concept4.cpp

@@ -1,38 +0,0 @@
-// Boost.Range library
-//
-// Copyright Neil Groves 2014. Use, modification and distribution is subject
-// to 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)
-//
-// For more information, see http://www.boost.org/libs/range
-//
-
-#include "mock_range.hpp"
-#include <boost/range/adaptor/filtered.hpp>
-
-namespace
-{
-
-struct always_true
-{
-    typedef bool result_type;
-
-    bool operator()(int) const
-    {
-        return true;
-    }
-};
-
-} // anonymous namespace
-
-int main(int, const char**)
-{
-    using boost::range::unit_test::mock_const_range;
-
-    // This next line should fail when Boost.Range concept checking is
-    // enabled since the filtered adaptor takes at least a ForwardRange.
-    return boost::adaptors::filter(
-        mock_const_range<boost::single_pass_traversal_tag>(),
-        always_true()).front();
-}