C object using blocks language extension

array_obj.h

#include <assert.h>
#include <stdlib.h>

#define Array_new(name, type, len)              \
  typedef void(^name##_each)(type);             \
  typedef void(^name##_each_i)(type, int);      \
                                                \
  struct {                                      \
    type *data;                                 \
    size_t length;                              \
    void(^free)();                              \
    type(^get)(int);                            \
    void(^set)(int, type);                      \
    void(^each)(name##_each);                   \
    void(^each_i)(name##_each_i);               \
  } name;                                       \
                                                \
  name.data = malloc(len * sizeof(type));       \
  name.length = len;                            \
                                                \
  name.free = ^{ free(name.data); };            \
                                                \
  name.get = ^(int i){                          \
    assert(i<= name.length);                    \
    return ((type *)name.data)[i];              \
  };                                            \
                                                \
  name.set = ^(int i, type value){              \
    assert(i<= name.length);                    \
    ((type*)name.data)[i] = value;              \
  };                                            \
                                                \
  name.each = ^(name##_each action){            \
    for (int i=0; i<name.length; ++i)           \
      action(name.get(i));                      \
  };                                            \
                                                \
  name.each_i = ^(name##_each_i action){        \
    for (int i=0; i<name.length; ++i)           \
      action(name.get(i), i);                   \
  };