core: move usefull template function

app/gui/node-editor.hpp

@@ -93,33 +93,6 @@ status_string(const status s) noexcept
     return str[static_cast<int>(s)];
 }
 
-template<class C>
-constexpr int
-length(const C& c) noexcept
-{
-    return static_cast<int>(c.size());
-}
-
-template<class T, size_t N>
-constexpr int
-length(const T (&array)[N]) noexcept
-{
-    (void)array;
-
-    return static_cast<int>(N);
-}
-
-template<typename Identifier>
-constexpr Identifier
-undefined() noexcept
-{
-    static_assert(
-      std::is_enum<Identifier>::value,
-      "Identifier must be a enumeration: enum class id : unsigned {};");
-
-    return static_cast<Identifier>(0);
-}
-
 enum class editor_id : u64;
 enum class cluster_id : u64;
 

lib/include/irritator/core.hpp

@@ -138,6 +138,33 @@ to_unsigned(Integer value)
     return static_cast<typename std::make_unsigned<Integer>::type>(value);
 }
 
+template<class C>
+constexpr int
+length(const C& c) noexcept
+{
+    return static_cast<int>(c.size());
+}
+
+template<class T, size_t N>
+constexpr int
+length(const T (&array)[N]) noexcept
+{
+    (void)array;
+
+    return static_cast<int>(N);
+}
+
+template<typename Identifier>
+constexpr Identifier
+undefined() noexcept
+{
+    static_assert(
+      std::is_enum<Identifier>::value,
+      "Identifier must be a enumeration: enum class id : unsigned {};");
+
+    return static_cast<Identifier>(0);
+}
+
 /*****************************************************************************
  *
  * Return status of many function