[DLG] Added try_get_child_value to Xml_element

juanmanzanero · Oct 17, 2023 · 12d622c · 12d622c
1 parent 2929e8d
commit 12d622c
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Showing 2 changed files with 42 additions and 6 deletions.
diff --git a/lion/foundation/type_traits.h b/lion/foundation/type_traits.h
@@ -143,12 +143,12 @@ template<class Class, typename SingleArg,
 constexpr auto is_not_copy_ctor() { return false; }
 
 #ifdef _MSC_VER
-    // In VS2017-2019 the "is_not_copy_ctor()" constexpr function does not
-    // work, we'll use a macro until the compiler catches up!
-#define WINDOWS_IS_NOT_COPY_CTOR(CLASSNAME)                                                                                                         \
-    template<typename... Args,                                                                                                                      \
-             typename std::enable_if_t<(sizeof...(Args) > 1u) ||                                                                                    \
-                                       !std::is_same_v<std::decay_t<std::tuple_element_t<0u, std::tuple<Args..., void> > >, CLASSNAME> >* = nullptr>
+// In VS2017-2019 the "is_not_copy_ctor()" constexpr function does not
+// work, we'll use a macro until the compiler catches up!
+#define WINDOWS_IS_NOT_COPY_CTOR(CLASSNAME)                                                                            \
+template<typename... Args,                                                                                             \
+         typename std::enable_if_t<(sizeof...(Args) > 1u) ||                                                           \
+         !std::is_same_v<std::decay_t<std::tuple_element_t<0u, std::tuple<Args..., void> > >, CLASSNAME> >* = nullptr>
 #endif
 
 

diff --git a/lion/io/Xml_element.h b/lion/io/Xml_element.h
@@ -54,6 +54,20 @@ class Xml_element
     //! @param[in] simply pass bool() to overload this function
     bool get_value(bool&&) { return to_bool(get_value()); }
 
+    //! Get value as an std::array<double, N>
+    //! @param[in] simply pass and std::array<double, N>{} to overload this function
+    template<std::size_t N>
+    std::array<double, N> get_value(std::array<double, N>&&)
+    {
+        const auto vec = get_value(std::vector<double>{});
+        if (vec.size() != N) {
+            throw std::runtime_error("Xml_element::get_value(std::array<double, N>): incorrect size.");
+        }
+        std::array<double, N> arr{};
+        std::copy_n(vec.cbegin(), N, arr.begin());
+        return arr;
+    }
+
     //! Set the value from string
     //! @param[in] val: new string value
     Xml_element& set_value(const std::string& val) { _e->SetText(val.c_str()); return *this;}
@@ -79,6 +93,28 @@ class Xml_element
     //! See if a child exists
     bool has_child(const std::string& name) const;
 
+    //! Try to get the value of a child, or return a default one
+    template<typename ValueType>
+    ValueType try_get_child_value(const std::string &childname, ValueType default_value,
+                                  bool warn_if_returning_default_value = true) const
+    {
+        if (has_child(childname)) {
+            return get_child(childname).get_value(ValueType{});
+        }
+        else {
+            if (warn_if_returning_default_value) {
+                std::cerr << "Xml_element::try_get_child_value: warning, xml element \""
+                    << get_name()
+                    << "\" does not contain child \""
+                    << childname << "\", returning a default value of \""
+                    << default_value
+                    << "\"."
+                    << std::endl;
+            }
+            return default_value;
+        }
+    }
+
     //! See if parent exists
     bool has_parent() const { return (_e->Parent()->ToElement() ? true : false); }