Add example/struct_to_tuple.cpp

doc/describe/examples.adoc

@@ -161,6 +161,18 @@ using boost::describe::operators::operator==;
 The rest of the relational operators are also provided and can
 be enabled similarly.
 
+[#example_struct_to_tuple]
+## struct_to_tuple
+
+This example defines a function `struct_to_tuple` that takes
+a described class type as an argument and returns a tuple of
+all its public members.
+
+[source]
+----
+include::../../example/struct_to_tuple.cpp[lines=5..-1]
+----
+
 [#example_to_json]
 ## Automatic Conversion to JSON
 

example/struct_to_tuple.cpp

@@ -0,0 +1,55 @@
+// Copyright 2021 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/describe.hpp>
+#include <tuple>
+
+namespace desc = boost::describe;
+
+template<class T, template<class...> class L, class... D>
+auto struct_to_tuple_impl( T const& t, L<D...> )
+{
+    return std::make_tuple( t.*D::pointer... );
+}
+
+template<class T, class Dm = desc::describe_members<T,
+    desc::mod_public | desc::mod_inherited>>
+auto struct_to_tuple( T const& t )
+{
+    return struct_to_tuple_impl( t, Dm() );
+}
+
+#include <boost/core/type_name.hpp>
+#include <iostream>
+
+struct X
+{
+    int a = 1;
+};
+
+BOOST_DESCRIBE_STRUCT(X, (), (a))
+
+struct Y
+{
+    float b = 3.14f;
+};
+
+BOOST_DESCRIBE_STRUCT(Y, (), (b))
+
+struct Z: X, Y
+{
+};
+
+BOOST_DESCRIBE_STRUCT(Z, (X, Y), ())
+
+int main()
+{
+    Z z;
+
+    auto tp = struct_to_tuple( z );
+
+    std::cout <<
+        boost::core::type_name<decltype(tp)>() << ": "
+        << std::get<0>(tp) << ", " << std::get<1>(tp);
+}

test/Jamfile

@@ -85,3 +85,4 @@ run ../example/json_rpc.cpp : : : $(CXX14) $(JSON) ;
 run ../example/hash_value.cpp : : : $(CXX14) ;
 run ../example/equality.cpp : : : $(CXX14) ;
 link ../example/console.cpp : $(CXX14) $(JSON) ;
+run ../example/struct_to_tuple.cpp : : : $(CXX14) ;