Add clone_utils::clone() method to clone automatically Shogun's objects.

src/shogun/base/SGObject.h

@@ -30,6 +30,7 @@
 #include <unordered_map>
 #include <utility>
 #include <vector>
+#include <shogun/util/clone.h>
 
 /** \namespace shogun
  * @brief all of classes and functions are contained in the shogun namespace
@@ -1004,16 +1005,7 @@ class CSGObject
 	 * @param step step
 	 * @param name tag's name
 	 */
-	template<class T,
-			typename std::enable_if_t<
-				!is_sg_vector<T>::value &&
-				!is_sg_matrix<T>::value>* = nullptr>
-	void observe(const int64_t step, const std::string& name) const;
-
-	template<class T,
-			typename std::enable_if_t<
-					is_sg_vector<T>::value ||
-					is_sg_matrix<T>::value>* = nullptr>
+	template <class T>
 	void observe(const int64_t step, const std::string& name) const;
 
 	/**
@@ -1315,27 +1307,13 @@ void CSGObject::observe(
 	this->observe(obs);
 }
 
-template<class T,
-		typename std::enable_if_t<
-				!is_sg_vector<T>::value &&
-				!is_sg_matrix<T>::value>*>
-void CSGObject::observe(const int64_t step, const std::string& name) const
-{
-	auto param = this->get_parameter(BaseTag(name));
-	auto obs = some<ObservedValueTemplated<T>>(
-		step, name, any_cast<T>(param.get_value()), param.get_properties());
-	this->observe(obs);
-}
-
-template<class T,
-		typename std::enable_if_t<
-				is_sg_vector<T>::value ||
-				is_sg_matrix<T>::value>*>
+template <class T>
 void CSGObject::observe(const int64_t step, const std::string& name) const
 {
 	auto param = this->get_parameter(BaseTag(name));
+	auto cloned = any_cast<T>(param.get_value());
 	auto obs = some<ObservedValueTemplated<T>>(
-			step, name, any_cast<T>(param.get_value()).clone(), param.get_properties());
+		step, name, static_cast<T>(clone_utils::clone(cloned)), param.get_properties());
 	this->observe(obs);
 }
 

src/shogun/util/clone.h

@@ -0,0 +1,63 @@
+/*
+* Written (W) 2019 Giovanni De Toni
+*/
+
+#include <type_traits>
+
+#ifndef SHOGUN_CLONE_H
+#define SHOGUN_CLONE_H
+
+namespace shogun {
+	namespace clone_utils
+	{
+
+		struct clone_by_cctor
+		{
+		};
+
+		struct clone_from_value : clone_by_cctor
+		{
+		};
+
+		struct clone_from_pointer : clone_from_value
+		{
+		};
+
+		template <class T, std::enable_if_t<std::is_copy_constructible<T>::value>* = nullptr>
+		inline T clone_impl(clone_by_cctor, const T& value)
+		{
+			return T(value);
+		}
+
+		template <class T>
+		inline auto clone_impl(clone_from_value, T& value)
+		-> decltype(value.clone())
+		{
+			return value.clone();
+		}
+
+		template <class T>
+		inline auto clone_impl(clone_from_pointer, T* value)
+		-> decltype(value->clone())
+		{
+			return value->clone();
+		}
+
+		/**
+		 * Clone a Shogun object by calling its clone() method.
+		 * It also works with non-Shogun object by using the copy
+		 * constructor.
+		 * @tparam T type
+		 * @param value value we want to clone
+		 * @return the cloned value
+		 */
+		template <class T>
+		inline auto clone(T& value)
+		-> decltype(clone_impl(clone_from_pointer(), value))
+		{
+			return clone_impl(clone_from_pointer(), value);
+		}
+	}
+}
+
+#endif //SHOGUN_CLONE_H