TICK_MEMBER_REQUIRES_OC for outside-class-definitions of members

Author: ajneu

doc/src/requires.md

@@ -57,6 +57,25 @@ struct foo
 };
 ```
 
+If the member is defined outside of the class, use `TICK_MEMBER_REQUIRES_OC` (OC: outside_class) outside the class. For example,
+```cpp
+template<class T>
+struct foo
+{
+    T x;
+
+    TICK_MEMBER_REQUIRES(is_incrementable<T>())
+    void up();
+};
+
+template<class T>
+TICK_MEMBER_REQUIRES_OC(is_incrementable<T>())
+void foo<T>::up()
+{
+    x++;
+}
+```
+
 TICK_PARAM_REQUIRES
 --------------------
 

tick/requires.h

@@ -53,14 +53,16 @@ trait(Ts&&...) noexcept
 
 #define TICK_CLASS_REQUIRES(...) typename std::enable_if<(__VA_ARGS__)>::type
 
-#define TICK_REQUIRES(...) bool TickPrivateBool ## __LINE__=true, typename std::enable_if<(TickPrivateBool##__LINE__ && __VA_ARGS__), int>::type = 0
+#define TICK_REQUIRES(...)    bool TickPrivateBool ## __LINE__=true, typename std::enable_if<(TickPrivateBool##__LINE__ && __VA_ARGS__), int>::type = 0
+#define TICK_REQUIRES_OC(...) bool TickPrivateBool ## __LINE__,      typename std::enable_if<(TickPrivateBool##__LINE__ && __VA_ARGS__), int>::type
 
-#define TICK_MEMBER_REQUIRES(...) template<TICK_REQUIRES(__VA_ARGS__)>
+#define TICK_MEMBER_REQUIRES(...)    template<TICK_REQUIRES(   __VA_ARGS__)>
+#define TICK_MEMBER_REQUIRES_OC(...) template<TICK_REQUIRES_OC(__VA_ARGS__)>
 
 #define TICK_PARAM_REQUIRES(...) \
 typename std::enable_if< \
     (tick::detail::param_extract<decltype(__VA_ARGS__)>::value), \
     typename tick::detail::private_enum<__LINE__>::type \
 >::type = tick::detail::private_enum<__LINE__>::type::na
 
-#endif
+#endif