A group of variadic macros

Question

I would like to have a group of variable number of arguments passed into a macro. I have following macros which is incorrect:

#define M_NARGS(...) M_NARGS_(_         


        

Answer 1

I'm not sure whether this is what you are looking for, but the parenthesised fruit and animal groups are not resolved. You can "flatten" them with your M_IDmacro, e.g.:

#define M_ID(...) __VA_ARGS__

#define FRUITS M_ID(apple, banana, cherry)
#define ANIMALS M_ID(dog, monkey)

#define ZOO_BLOCK(NAME, FRTS, ANMLS) struct NAME##Block {   \
  M_FOR_EACH(DEFINE_FRUITS, FRTS)                           \
  M_FOR_EACH(DEFINE_ANIMALS, ANMLS)                          \
}

#define DEFINE_FRUITS(F) Fruit F;
#define DEFINE_ANIMALS(F) Animal F;

ZOO_BLOCK(MyZoo, FRUITS, ANIMALS);

This, together with correcting a minor typo in DEFINE_ANIMAL/S yields:

struct MyZooBlock { 
    Fruit apple;
    Fruit banana;
    Fruit cherry;
    Animal dog;
    Animal monkey;
};