Creating Tables in C

gistfile1.c

#include <stdio.h>

/* BEGIN HACKERY */

typedef struct field {
    enum {
      TABLE_NAME,
      TABLE_FIELD,
      TABLE_TERMINATOR
    } tag;
    union {
      char* table_name;
      struct { char* type;
               char* opts;
               char* name; } field;
    } val;
} Field;
#define table(_name, ...) Field _name[] = { {.tag = TABLE_NAME, .val = {.table_name = #_name}} , __VA_ARGS__ ,  {.tag = TABLE_TERMINATOR}  }
#define field(_name,_type,_opts)  {.tag = TABLE_FIELD, .val = {.field = {.type =_type, .name = #_name, .opts = _opts}}} 

typedef Field* Table;

/* END HACKERY */

/* BEGIN AWESOME */

table(BlogPost,
   field(Id,"INTEGER","PRIMARY KEY AUTOINCREMENT"),
   field(Title, "VARCHAR(200)", ""),
   field(Body, "TEXT", "")
);

/* END AWESOME */

void printTableDef(Table tableDef) {
   int i;
   for (i = 0; tableDef[i].tag != TABLE_TERMINATOR; i++) {
      if (tableDef[i].tag == TABLE_NAME) {
         printf("CREATE TABLE %s (", tableDef[i].val.table_name);
      } else {
         printf("%s %s %s", tableDef[i].val.field.name, tableDef[i].val.field.type, tableDef[i].val.field.opts);
         printf(tableDef[i+1].tag == TABLE_TERMINATOR ? ")" : ", ");
      }
   }
   printf(";\n");
}

int main () {
   printTableDef(BlogPost);
   return 0;
}

what is this i don't even.....