template queue in c
#define define_list(type) \
\
struct _list_##type; \
\
typedef struct \
{ \
int (*is_empty)(const struct _list_##type*); \
size_t (*size)(const struct _list_##type*); \
const type (*front)(const struct _list_##type*); \
void (*push_front)(struct _list_##type*, type); \
} _list_functions_##type; \
\
typedef struct _list_elem_##type \
{ \
type _data; \
struct _list_elem_##type* _next; \
} list_elem_##type; \
\
typedef struct _list_##type \
{ \
size_t _size; \
list_elem_##type* _first; \
list_elem_##type* _last; \
_list_functions_##type* _functions; \
} List_##type; \
\
List_##type* new_list_##type(); \
bool list_is_empty_##type(const List_##type* list); \
size_t list_size_##type(const List_##type* list); \
const type list_front_##type(const List_##type* list); \
void list_push_front_##type(List_##type* list, type elem); \
\
bool list_is_empty_##type(const List_##type* list) \
{ \
return list->_size == 0; \
} \
\
size_t list_size_##type(const List_##type* list) \
{ \
return list->_size; \
} \
\
const type list_front_##type(const List_##type* list) \
{ \
return list->_first->_data; \
} \
\
void list_push_front_##type(List_##type* list, type elem) \
{ \
... \
} \
\
_list_functions_##type _list_funcs_##type = { \
&list_is_empty_##type, \
&list_size_##type, \
&list_front_##type, \
&list_push_front_##type, \
}; \
\
List_##type* new_list_##type() \
{ \
List_##type* res = (List_##type*) malloc(sizeof(List_##type)); \
res->_size = 0; \
res->_first = NULL; \
res->_functions = &_list_funcs_##type; \
return res; \
}
#define List(type) \
List_##type
#define new_list(type) \
new_list_##type()