ENH: add reverse iteration macros

- forAllReverseIters and forAllReverseConstIters macros
- stdFoam::rbegin(), stdFoam::rend()
  stdFoam::crbegin(), stdFoam::crend()

applications/test/List/Test-List.C

@@ -105,6 +105,22 @@ int main(int argc, char *argv[])
     };
     Info<< "list2: " << list2 << endl;
 
+    Info<< "forAllConstIters(list2): ";
+    forAllConstIters(list2, iter) { Info<< " " << *iter; }
+    Info<< endl;
+
+    Info<< "forAllReverseConstIters(list2): ";
+    forAllReverseConstIters(list2, iter) { Info<< " " << *iter; }
+    Info<< endl;
+
+    Info<< "forAllConstIters(list2): ";
+    forAllIters(list2, iter) { *iter *= 2; Info<< " " << *iter; }
+    Info<< endl;
+
+    Info<< "forAllReverseConstIters(list2): ";
+    forAllReverseIters(list2, iter) { *iter *= 0.5; Info<< " " << *iter; }
+    Info<< endl;
+
     list1.append(list2);
     Info<< "list1.append(list2): " << list1 << endl;
 

src/OpenFOAM/include/stdFoam.H

@@ -34,13 +34,15 @@ Description
     control over which definitions are used within the OpenFOAM code-base.
 
 SeeAlso
-    - http://en.cppreference.com/w/cpp/iterator/end
     - http://en.cppreference.com/w/cpp/iterator/begin
+    - http://en.cppreference.com/w/cpp/iterator/end
+    - http://en.cppreference.com/w/cpp/iterator/rbegin
+    - http://en.cppreference.com/w/cpp/iterator/rend
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef StdFoam_H
-#define StdFoam_H
+#ifndef stdFoam_H
+#define stdFoam_H
 
 #include <initializer_list>
 #include <utility>
@@ -52,7 +54,9 @@ namespace stdFoam
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
-//- Return iterator to the beginning of the container \a c or array.
+// Forward iteration
+
+//- Return iterator to the beginning of the container \a c.
 //  Definition as per std::begin C++17
 template<class C>
 constexpr auto begin(C& c) -> decltype(c.begin())
@@ -60,7 +64,7 @@ constexpr auto begin(C& c) -> decltype(c.begin())
     return c.begin();
 }
 
-//- Return const_iterator to the beginning of the container \a c or array.
+//- Return const_iterator to the beginning of the container \a c.
 //  Definition as per std::begin C++17
 template<class C>
 constexpr auto begin(const C& c) -> decltype(c.begin())
@@ -68,7 +72,7 @@ constexpr auto begin(const C& c) -> decltype(c.begin())
     return c.begin();
 }
 
-//- Return const_iterator to the beginning of the container \a c or array.
+//- Return const_iterator to the beginning of the container \a c.
 //  Definition as per std::cbegin C++17
 template<class C>
 constexpr auto cbegin(const C& c) -> decltype(c.begin())
@@ -76,7 +80,7 @@ constexpr auto cbegin(const C& c) -> decltype(c.begin())
     return c.begin();
 }
 
-//- Return iterator to the end of the container \a c or array.
+//- Return iterator to the end of the container \a c array.
 //  Definition as per std::end C++17
 template<class C>
 constexpr auto end(C& c) -> decltype(c.end())
@@ -84,7 +88,7 @@ constexpr auto end(C& c) -> decltype(c.end())
     return c.end();
 }
 
-//- Return const_iterator to the end of the container \a c or array.
+//- Return const_iterator to the end of the container \a c array.
 //  Definition as per std::end C++17
 template<class C>
 constexpr auto end(const C& c) -> decltype(c.end())
@@ -92,7 +96,7 @@ constexpr auto end(const C& c) -> decltype(c.end())
     return c.end();
 }
 
-//- Return const_iterator to the end of the container \a c or array.
+//- Return const_iterator to the end of the container \a c.
 //  Definition as per std::cend C++17
 template<class C>
 constexpr auto cend(const C& c) -> decltype(c.end())
@@ -101,6 +105,57 @@ constexpr auto cend(const C& c) -> decltype(c.end())
 }
 
 
+// Reverse iteration
+
+//- Return reverse_iterator to the reverse-begin of container \a c.
+//  Definition as per std::rbegin C++17
+template<class C>
+constexpr auto rbegin(C& c) -> decltype(c.rbegin())
+{
+    return c.rbegin();
+}
+
+//- Return const_reverse_iterator to the reverse-begin of container \a c.
+//  Definition as per std::rbegin C++17
+template<class C>
+constexpr auto rbegin(const C& c) -> decltype(c.rbegin())
+{
+    return c.rbegin();
+}
+
+//- Return const_reverse_iterator to the reverse-begin of container \a c.
+//  Definition as per std::crbegin C++17
+template<class C>
+constexpr auto crbegin(const C& c) -> decltype(c.rbegin())
+{
+    return c.rbegin();
+}
+
+//- Return reverse_iterator to reverse-end of container \a c.
+//  Definition as per std::rend C++17
+template<class C>
+constexpr auto rend(C& c) -> decltype(c.rend())
+{
+    return c.rend();
+}
+
+//- Return const_reverse_iterator to reverse-end of container \a c.
+//  Definition as per std::rend C++17
+template<class C>
+constexpr auto rend(const C& c) -> decltype(c.rend())
+{
+    return c.rend();
+}
+
+//- Return const_reverse_iterator to reverse-end of container \a c.
+//  Definition as per std::crend C++17
+template<class C>
+constexpr auto crend(const C& c) -> decltype(c.rend())
+{
+    return c.rend();
+}
+
+
 } // End namespace stdFoam
 
 
@@ -143,6 +198,43 @@ constexpr auto cend(const C& c) -> decltype(c.end())
     )
 
 
+//- Rverse iterate across elements in the \a container object of type
+//  \a Container.
+//  \par Usage
+//  \code
+//  forAllReverseIters(container, iter)
+//  {
+//      statements;
+//  }
+//  \endcode
+//  \sa forAllReverseConstIters
+#define forAllReverseIters(container,iter)                                     \
+    for                                                                        \
+    (                                                                          \
+        auto iter = stdFoam::rbegin(container);                                \
+        iter != stdFoam::rend(container);                                      \
+        --iter                                                                 \
+    )
+
+
+//- Reverse iterate across elements of \a container object with const access.
+//  \par Usage
+//  \code
+//  forAllReverseConstIters(container, iter)
+//  {
+//      statements;
+//  }
+//  \endcode
+//  \sa forAllReverseIters
+#define forAllReverseConstIters(container,iter)                                \
+    for                                                                        \
+    (                                                                          \
+        auto iter = stdFoam::crbegin(container);                               \
+        iter != stdFoam::crend(container);                                     \
+        --iter                                                                 \
+    )
+
+
 //- Loop across all elements in \a list
 // \par Usage
 // \code
@@ -169,6 +261,8 @@ constexpr auto cend(const C& c) -> decltype(c.end())
     for (Foam::label i=(list).size()-1; i>=0; --i)
 
 
+// Compatibility macros for pre C++11
+
 //- Iterate across all elements in the \a container object
 //  of type \a Container.
 //  \par Usage