Yarp: Introduce standardized methods for retrieving const_iterator in VectorOf

[GiulioRomualdi]

In order to access a const iterator of a yarp::sig::vector the methods cbegin()/cend() have to be used. Renaming the methods by removing the c may be useful when template functions are implemented. I.e. std:: vector<> uses the begin()/end() to access to const iterators.

The new methods can be easily implemented as follows. Since cbegin() and cend() will not be touched, this new feature will guarantee backward-compatibility

diff --git a/src/libYARP_sig/src/yarp/sig/Vector.h b/src/libYARP_sig/src/yarp/sig/Vector.h
index 016f354d3..9e13e4c16 100644
--- a/src/libYARP_sig/src/yarp/sig/Vector.h
+++ b/src/libYARP_sig/src/yarp/sig/Vector.h
@@ -550,6 +550,22 @@ public:
         return first + len;
     }

+    /**
+     * @brief Returns a const iterator to the beginning of the VectorOf
+     * @note At the moment iterator is implemented as a pointer, it may change in the future.
+     * For this reason it should not be used as a pointer to the data, use data() instead.
+     */
+    const_iterator begin() const noexcept {
+        return first;
+    }
+
+    /**
+     * @brief Returns a const iterator to the end of the VectorOf.
+     */
+    const_iterator end() const noexcept {
+        return first + len;
+    }
+
     /**
      * @brief Returns a const iterator to the beginning of the VectorOf
      * @note At the moment iterator is implemented as a pointer, it may change in the future.

What do you think? @drdanz @traversaro @Nicogene

[traversaro]

I think it makes sense, probably it could make sense to also deprecate cbegin and cend if this methods are implemented.

[Nicogene]

Actually in std::vector begin/end-cbegin/cend coexist see https://en.cppreference.com/w/cpp/container/vector/begin.

I would keep all the methods without deprecating it.

[traversaro]

Actually in std::vector begin/end-cbegin/cend coexist see https://en.cppreference.com/w/cpp/container/vector/begin.

I will keep all the methods without deprecating it.

I was not aware of this, yes then it make sense to keep both.

[GiulioRomualdi]

Me neither. If you (@nicogene) want, I can handle the PR in which begin() / end() are introduced

[Nicogene]

@GiulioRomualdi go ahead :+1:

[drdanz]

:+1: For adding const begin and end, :-1: for deprecating cbegin and cend which are required to return a const iterator when you have a non-const object

[drdanz]

Fixed by #2182