Switched to std::optional

Author: andrea.mancuso

csscolorparser.cpp

@@ -176,7 +176,7 @@ std::vector<std::string> split(const std::string& s, char delim) {
     return elems;
 }
 
-optional<Color> parse(const std::string& css_str) {
+std::optional<Color> parse(const std::string& css_str) {
     std::string str = css_str;
 
     // Remove all whitespace, not compliant, but should just be more accepting.

csscolorparser.hpp

@@ -27,13 +27,10 @@
 
 #include <string>
 #include <cmath>
-#include <experimental/optional>
+#include <optional>
 
 namespace CSSColorParser {
 
-template <class T>
-using optional = std::experimental::optional<T>;
-
 struct Color {
     inline Color() {
     }
@@ -52,7 +49,7 @@ inline bool operator!=(const Color& lhs, const Color& rhs) {
     return !(lhs == rhs);
 }
 
-optional<Color> parse(const std::string& css_str);
+std::optional<Color> parse(const std::string& css_str);
 
 } // namespace CSSColorParser