Add QX_EVAL_EACH(). Fixed arg, varadic macro functions

Author: oblivioncth

lib/utility/include/qx/utility/qx-macros.h

@@ -18,6 +18,7 @@
 
 #define __QX_FOR_EACH_NEXT() __QX_FOR_EACH_APPLY_AND_ITERATE
 #define __QX_FOR_EACH_NEXT_DELIM() __QX_FOR_EACH_APPLY_AND_ITERATE_DELIM
+#define __QX_EVAL_EACH_NEXT() __QX_EVAL_EACH_APPLY_AND_ITERATE
 
 #define __QX_FOR_EACH_APPLY_AND_ITERATE(macro, first, ...) \
     macro(first) \
@@ -26,6 +27,10 @@
 #define __QX_FOR_EACH_APPLY_AND_ITERATE_DELIM(macro, first, ...) \
     macro(first) \
     __VA_OPT__(, __QX_FOR_EACH_NEXT_DELIM __QX_MACRO_CALL (macro, __VA_ARGS__))
+
+#define __QX_EVAL_EACH_APPLY_AND_ITERATE(arg, first, ...) \
+    first(arg) \
+    __VA_OPT__(__QX_EVAL_EACH_NEXT __QX_MACRO_CALL (arg, __VA_ARGS__))
 /*! @endcond */
 
 // User
@@ -43,4 +48,7 @@ inline size_t qHash(const T& t, size_t seed) { \
 #define QX_FOR_EACH_DELIM(macro, ...) \
     __VA_OPT__(__QX_MACRO_EVALUATE(__QX_FOR_EACH_APPLY_AND_ITERATE_DELIM(macro, __VA_ARGS__)))
 
+#define QX_EVAL_EACH(arg, ...) \
+    __VA_OPT__(__QX_MACRO_EVALUATE(__QX_EVAL_EACH_APPLY_AND_ITERATE(arg, __VA_ARGS__)))
+
 #endif // QX_MACROS_H

lib/utility/src/qx-macros.dox

@@ -50,3 +50,21 @@
  *  QX_FOR_EACH_DELIM(F, 1, 4, 10) // -> F(1), F(4), F(10)
  *  @endcode
  */
+
+ /*!
+ *  @def QX_EVAL_EACH(arg, ...)
+ *
+ *  This function-like macro acts like a fold expression for its variadic arguments.
+ *  It produces the result of calling all trailing macro functions with the argument
+ *  @a arg.
+ *
+ *  For example:
+ *  @code{.cpp}
+ *  #define F(x) //...
+ *  #define G(x) //...
+ *  #define H(x) //...
+ *  QX_EVAL_EACH(10, F, G, H) // -> F(10) G(10) H(10)
+ *  @endcode
+ *
+ *  @sa QX_FOR_EACH()
+ */