pfr_fields_view

.github/workflows/ci.yml

@@ -344,6 +344,8 @@ jobs:
           git submodule init libs/type_traits
           git submodule init libs/typeof
           git submodule init libs/utility
+          git submodule init libs/pfr
+          git submodule init libs/mp11
           git submodule init libs/headers tools/boost_install tools/build
           git submodule update
           rm -rf libs/fusion
@@ -452,6 +454,8 @@ jobs:
           git submodule init libs/type_traits
           git submodule init libs/typeof
           git submodule init libs/utility
+          git submodule init libs/pfr
+          git submodule init libs/mp11
           git submodule init libs/headers tools/boost_install tools/build
           git submodule update
           rm -rf libs/fusion
@@ -464,4 +468,4 @@ jobs:
 
           ./b2 -j`(nproc || sysctl -n hw.ncpu) 2> /dev/null` libs/fusion/test toolset=$TOOLSET cxxstd=$CXXSTD
 
-          fi
+          fi

CMakeLists.txt

@@ -23,5 +23,7 @@ target_link_libraries(boost_fusion
         Boost::type_traits
         Boost::typeof
         Boost::utility
+        Boost::pfr
+        Boost::mp11
         Boost::functional
 )

appveyor.yml

@@ -82,6 +82,8 @@ install:
   - git submodule init libs/type_traits
   - git submodule init libs/typeof
   - git submodule init libs/utility
+  - git submodule init libs/pfr
+  - git submodule init libs/mp11
 
   - git submodule init libs/headers tools/boost_install tools/build
   - git submodule update

doc/algorithm.qbk

@@ -2,6 +2,7 @@
     Copyright (C) 2001-2011 Joel de Guzman
     Copyright (C) 2006 Dan Marsden
     Copyright (C) 2010 Christopher Schmidt
+    Copyright (c) 2022 Denis Mikhailov
 
     Use, modification and distribution is subject to the Boost Software
     License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
@@ -139,6 +140,91 @@ Linear, exactly `__result_of_size__<Sequence>::value`.
 
 [endsect]
 
+[section pfr_fields]
+
+[caution This function requires at least C++14! Pre C++14 compilers (C++11, C++03...) are not supported.]
+
+[heading Description]
+For an user defined structure `agg`, `pfr_fields` returns a new sequence
+with elements extracted by using __boost_pfr__.
+This function does not require macro or boilerplate code from an user defined structure
+, unlike __adapt_struct__, and can be used as a replacement for __adapt_struct__.
+
+[heading Synopsis]
+    template<
+        typename Aggregate
+        >
+    typename __result_of_pfr_fields__<Aggregate>::type pfr_fields(
+        Aggregate& agg);
+
+    template<
+        typename Aggregate
+        >
+    typename __result_of_pfr_fields__<Aggregate const>::type pfr_fields(
+        Aggregate const& agg);
+
+[table Parameters
+    [[Parameter][Requirement][Description]]
+    [[`agg`][A model of __simple_aggregate__][Operation's argument]]
+]
+
+[heading Expression Semantics]
+    __pfr_fields__(agg);
+
+[*Return type]: A model of __random_access_sequence__
+
+[*Semantics]: Returns a sequence with all elements from user defined structure.
+
+[heading Complexity]
+Constant.
+
+[heading Header]
+
+    #include <boost/fusion/algorithm/auxiliary/pfr_fields.hpp>
+    #include <boost/fusion/include/pfr_fields.hpp>
+
+[note This algorithm won't be defined by inclusion of 'boost/fusion/algorithm/auxiliary.hpp' or 'boost/fusion/algorithm.hpp'. ]
+
+[heading Example]
+
+    struct some_person {       // SimpleAggregate
+        std::string name;
+        unsigned birth_year = 0;
+    };
+
+    some_person val{"Edgar Allan Poe", 1809};
+    std::cout << __pfr_fields__(val) << std::endl; // (Edgar Allan Poe 1809)
+
+[heading Example]
+
+    struct empty {             // SimpleAggregate
+    };
+
+    struct aggregate : empty { // not a SimpleAggregate because of inheritance
+        std::string name;
+        int age = 0;
+        boost::uuids::uuid uuid;
+    };
+
+    aggregate val{"Edgar Allan Poe", 1809, {}};
+    __pfr_fields__(val); // non-portable behavior
+
+[heading Example]
+
+    using some_person = __vector__< // not a SimpleAggregate
+        std::string
+      , unsigned
+    >;
+
+    some_person val("Edgar Allan Poe", 1809);
+    __pfr_fields__(val); // won't compile
+
+[heading See also]
+
+__boost_pfr__
+
+[endsect]
+
 [endsect]
 
 [section Metafunctions]
@@ -215,6 +301,48 @@ Constant.
 
 [endsect]
 
+[section pfr_fields]
+
+[caution This metafunction requires at least C++14! Pre C++14 compilers (C++11, C++03...) are not supported.]
+
+[heading Description]
+A metafunction returning the result type of applying __pfr_fields__.
+
+[heading Synopsis]
+    template <typename Aggregate>
+    struct pfr_fields
+    {
+        typedef __unspecified__ type;
+    };
+
+[table Parameters
+    [[Parameter] [Requirement] [Description]]
+    [[`Aggregate`] [A model of __simple_aggregate__] [Operation's argument]]
+]
+
+[heading Expression Semantics]
+    result_of::pfr_fields<Aggregate>::type
+
+[*Return type]: A model of __random_access_sequence__
+
+[*Semantics]: Returns a sequence with all elements from user defined structure.
+
+[heading Complexity]
+Constant.
+
+[heading Header]
+
+    #include <boost/fusion/algorithm/auxiliary/pfr_fields.hpp>
+    #include <boost/fusion/include/pfr_fields.hpp>
+
+[note This algorithm won't be defined by inclusion of 'boost/fusion/algorithm/auxiliary.hpp' or 'boost/fusion/algorithm.hpp'. ]
+
+[heading See also]
+
+__boost_pfr__
+
+[endsect]
+
 [endsect]
 
 [endsect]

doc/fusion.qbk

@@ -48,6 +48,9 @@
 [def __boost_func_forward__     [@http://www.boost.org/libs/functional/forward Boost.Functional/Forward Library]]
 [def __boost_func_factory__     [@http://www.boost.org/libs/functional/factory Boost.Functional/Factory Library]]
 [def __boost_func_hash__        [@http://www.boost.org/doc/html/hash.html Boost.ContainerHash Library]]
+[def __boost_pfr__              [@http://www.boost.org/doc/html/boost_pfr.html Boost.PFR Library]]
+[def __boost_pfr_lims__         [@http://www.boost.org/doc/html/boost_pfr/limitations_and_configuration.html Boost.PFR Limitations and Configuration]]
+[def __simple_aggregate__       [@http://www.boost.org/doc/html/boost_pfr/limitations_and_configuration.html SimpleAggregate]]
 [def __std_pair_doc__           [@http://en.cppreference.com/w/cpp/utility/pair `std::pair`]]
 [def __std_tuple_doc__          [@http://en.cppreference.com/w/cpp/utility/tuple `std::tuple`]]
 [def __std_plus_doc__           [@http://en.cppreference.com/w/cpp/utility/functional/plus `std::plus`]]
@@ -131,12 +134,14 @@
 [def __zip_view__               [link fusion.view.zip_view `zip_view`]]
 [def __flatten_view__           [link fusion.view.flatten_view `flatten_view`]]
 [def __identity_view__          [link fusion.view.identity_view `identity_view`]]
+[def __pfr_fields_view__        [link fusion.view.pfr_fields_view `pfr_fields_view`]]
 
 [def __array__                  [link fusion.adapted.array array]]
 [def __std_pair__               [link fusion.adapted.std__pair `std::pair`]]
 [def __boost_array__            [link fusion.adapted.boost__array `boost::array`]]
 [def __mpl_sequence__           [link fusion.adapted.mpl_sequence mpl sequence]]
 [def __adapt_tpl_struct__       [link fusion.adapted.adapt_tpl_struct `BOOST_FUSION_ADAPT_TPL_STRUCT`]]
+[def __adapt_struct__           [link fusion.adapted.adapt_struct `BOOST_FUSION_ADAPT_STRUCT`]]
 [def __adapt_struct_named__     [link fusion.adapted.adapt_struct_named `BOOST_FUSION_ADAPT_STRUCT_NAMED`]]
 [def __adapt_struct_named_ns__  [link fusion.adapted.adapt_struct_named `BOOST_FUSION_ADAPT_STRUCT_NAMED_NS`]]
 [def __adapt_assoc_tpl_struct__ [link fusion.adapted.adapt_assoc_tpl_struct `BOOST_FUSION_ADAPT_ASSOC_TPL_STRUCT`]]
@@ -229,6 +234,8 @@
 [def __result_of_copy__         [link fusion.algorithm.auxiliary.metafunctions.copy `result_of::copy`]]
 [def __move__                   [link fusion.algorithm.auxiliary.functions.move `move`]]
 [def __result_of_move__         [link fusion.algorithm.auxiliary.metafunctions.move `result_of::move`]]
+[def __pfr_fields__             [link fusion.algorithm.auxiliary.functions.pfr_fields `pfr_fields`]]
+[def __result_of_pfr_fields__   [link fusion.algorithm.auxiliary.metafunctions.pfr_fields `result_of::pfr_fields`]]
 [def __fold__                   [link fusion.algorithm.iteration.functions.fold `fold`]]
 [def __result_of_fold__         [link fusion.algorithm.iteration.metafunctions.fold `result_of::fold`]]
 [def __reverse_fold__           [link fusion.algorithm.iteration.functions.reverse_fold `reverse_fold`]]

doc/html/index.html

@@ -164,6 +164,7 @@
 <dt><span class="section"><a href="fusion/view/transform_view.html">transform_view</a></span></dt>
 <dt><span class="section"><a href="fusion/view/reverse_view.html">reverse_view</a></span></dt>
 <dt><span class="section"><a href="fusion/view/identity_view.html">identity_view</a></span></dt>
+<dt><span class="section"><a href="fusion/view/pfr_fields_view.html">pfr_fields_view</a></span></dt>
 <dt><span class="section"><a href="fusion/view/nview.html">nview</a></span></dt>
 <dt><span class="section"><a href="fusion/view/repetitive_view.html">repetitive_view</a></span></dt>
 <dt><span class="section"><a href="fusion/view/flatten_view.html">flatten_view</a></span></dt>

doc/organization.qbk

@@ -61,6 +61,7 @@ link against.
     * transform_view
     * zip_view
     * identity_view
+    * pfr_fields_view
 * container
     * deque
     * list

doc/sequence.qbk

@@ -134,6 +134,7 @@ For any Forward Sequence s the following invariants always hold:
 * __reverse_view__
 * __zip_view__
 * __identity_view__
+* __pfr_fields_view__
 
 [endsect]
 
@@ -203,6 +204,7 @@ are not defined in __forward_sequence__.
 * __transform_view__ (where adapted sequence is a Bidirectional Sequence)
 * __zip_view__       (where adapted sequences are models of Bidirectional Sequence)
 * __identity_view__  (where adapted sequence is a Bidirectional Sequence)
+* __pfr_fields_view__
 
 [endsect]
 
@@ -292,6 +294,7 @@ are not defined in __bidirectional_sequence__.
 * __transform_view__ (where adapted sequence is a Random Access Sequence)
 * __zip_view__       (where adapted sequences are models of Random Access Sequence)
 * __identity_view__  (where adapted sequence is a Random Access Sequence)
+* __pfr_fields_view__
 
 [endsect]
 

doc/view.qbk

@@ -721,4 +721,96 @@ defined in the implemented models.
 
 [endsect]
 
+[section pfr_fields_view]
+
+[caution This view requires at least C++14! Pre C++14 compilers (C++11, C++03...) are not supported.]
+
+[heading Description]
+
+`pfr_fields_view` is a view into an user defined structure as a random access sequence.
+This view does not require macro or boilerplate code from an user defined structure
+, unlike __adapt_struct__, and can be used as a replacement for __adapt_struct__.
+
+[heading Header]
+
+    #include <boost/fusion/view/pfr_fields_view.hpp>
+    #include <boost/fusion/include/pfr_fields_view.hpp>
+
+[note This view won't be defined by inclusion of 'boost/fusion/view.hpp'. ]
+
+[heading Synopsis]
+
+    template <typename Aggregate>
+    struct pfr_fields_view;
+
+[heading Template parameters]
+
+[table
+    [[Parameter]            [Description]                                                        [Default]]
+    [[`Aggregate`]          [An user defined structure, satisfying __simple_aggregate__ concept] []]
+]
+
+[heading Model of]
+
+* __random_access_sequence__
+
+[variablelist Notation
+    [[`P`]              [A `pfr_fields_view` type]]
+    [[`p`, `p2`]        [Instances of `pfr_fields_view`]]
+    [[`a`]              [An instance of __simple_aggregate__]]
+]
+
+[heading Expression Semantics]
+
+Semantics of an expression is defined only where it differs from, or is not
+defined in __random_access_sequence__.
+
+[table
+    [[Expression]           [Semantics]]
+    [[`P(a)`]               [Creates a `pfr_fields_view` from `a`.]]
+    [[`P(p)`]               [Copy constructs a `pfr_fields_view` from another `pfr_fields_view`, `p`.]]
+    [[`p = p2`]             [Assigns to a `pfr_fields_view`, `p`, from another `pfr_fields_view`, `p2`.]]
+]
+
+[heading Example]
+
+    struct some_person {       // SimpleAggregate
+        std::string name;
+        unsigned birth_year = 0;
+    };
+
+    some_person val{"Edgar Allan Poe", 1809};
+    __pfr_fields_view__<some_person> view(val);
+    std::cout << view << std::endl; // (Edgar Allan Poe 1809)
+
+[heading Example]
+
+    struct empty {             // SimpleAggregate
+    };
+
+    struct aggregate : empty { // not a SimpleAggregate because of inheritance
+        std::string name;
+        int age = 0;
+        boost::uuids::uuid uuid;
+    };
+
+    aggregate val{"Edgar Allan Poe", 1809, {}};
+    __pfr_fields_view__<aggregate> view(val); // non-portable behavior
+
+[heading Example]
+
+    using some_person = __vector__< // not a SimpleAggregate
+        std::string
+      , unsigned
+    >;
+
+    some_person val("Edgar Allan Poe", 1809);
+    __pfr_fields_view__<some_person> view(val); // won't compile
+
+[heading See also]
+
+__boost_pfr__
+
+[endsect]
+
 [endsect]

include/boost/fusion/algorithm/auxiliary.hpp

@@ -13,4 +13,12 @@
 #include <boost/fusion/algorithm/auxiliary/move.hpp>
 #endif
 
+// Unfortunately, there is no way to determine the compatibility of the pfr library with the current compiler.
+// The "boost/fusion/algorithm/auxiliary/pfr_fields.hpp" include has been commented out to ensure backward compatibility
+// Please include it manually in your project
+
+// #if !defined(BOOST_FUSION_NO_PFR)
+// #include <boost/fusion/algorithm/auxiliary/pfr_fields.hpp>
+// #endif
+
 #endif