#define c_defer(...) \
    for (int _i = 1; _i; _i = 0, __VA_ARGS__)

#define c_with(...) c_MACRO_OVERLOAD(c_with, __VA_ARGS__)
#define c_with_2(declvar, drop) \
    for (declvar, *_i, **_ip = &_i; _ip; _ip = 0, drop)
#define c_with_3(declvar, pred, drop) \
    for (declvar, *_i, **_ip = &_i; _ip && (pred); _ip = 0, drop)

#define c_scope(...) c_MACRO_OVERLOAD(c_scope, __VA_ARGS__)
#define c_scope_2(init, drop) \
    for (int _i = (init, 1); _i; _i = 0, drop)
#define c_scope_3(init, pred, drop) \
    for (int _i = (init, 1); _i && (pred); _i = 0, drop)

#define c_auto(...) c_MACRO_OVERLOAD(c_auto, __VA_ARGS__)
#define c_auto_2(C, a) \
    c_with_2(C a = C##_init(), C##_drop(&a))
#define c_auto_3(C, a, b) \
    c_with_2(c_EXPAND(C a = C##_init(), b = C##_init()), \
            (C##_drop(&b), C##_drop(&a)))
#define c_auto_4(C, a, b, c) \
    c_with_2(c_EXPAND(C a = C##_init(), b = C##_init(), c = C##_init()), \
            (C##_drop(&c), C##_drop(&b), C##_drop(&a)))
#define c_auto_5(C, a, b, c, d) \
    c_with_2(c_EXPAND(C a = C##_init(), b = C##_init(), c = C##_init(), d = C##_init()), \
            (C##_drop(&d), C##_drop(&c), C##_drop(&b), C##_drop(&a)))