// C

/* Common type for all collectable objects */
typedef struct GCObject {
  struct GCObject *next; 
  lu_byte tt; 
  lu_byte marked;
} GCObject;

typedef struct TValue {
  union {
    struct GCObject *gc;    /* collectable objects */
    void *p;         /* light userdata */
    lua_CFunction f; /* light C functions */
    lua_Integer i;   /* integer numbers */
    lua_Number n;    /* float numbers */
    /* not used, but may avoid warnings for uninitialized value */
    lu_byte ub;
  } value_; 
  lu_byte tt_;
} TValue;

// C

typedef struct Proto {
  // collectable header
  struct GCObject *next; 
  lu_byte tt; 
  lu_byte marked;
  
  lu_byte numparams;  /* number of fixed (named) parameters */
  lu_byte is_vararg;
  lu_byte maxstacksize;  /* number of registers needed by this function */
  int sizeupvalues;  /* size of 'upvalues' */
  int sizek;  /* size of 'k' */
  int sizecode;
  int sizelineinfo;
  int sizep;  /* size of 'p' */
  int sizelocvars;
  int sizeabslineinfo;  /* size of 'abslineinfo' */
  int linedefined;  /* debug information  */
  int lastlinedefined;  /* debug information  */
  TValue *k;  /* constants used by the function */
  Instruction *code;  /* opcodes */
  struct Proto **p;  /* functions defined inside the function */
  Upvaldesc *upvalues;  /* upvalue information */
  ls_byte *lineinfo;  /* information about source lines (debug information) */
  AbsLineInfo *abslineinfo;  /* idem */
  LocVar *locvars;  /* information about local variables (debug information) */
  TString  *source;  /* used for debug information */
  GCObject *gclist;
} Proto;

// C

typedef struct CClosure {
  // collectable header
  struct GCObject *next; 
  lu_byte tt; 
  lu_byte marked; 
  
  lu_byte nupvalues; 
  GCObject *gclist;
  lua_CFunction f;
  TValue upvalue[1];  /* list of upvalues */
} CClosure;


typedef struct LClosure {
  // collectable header
  struct GCObject *next; 
  lu_byte tt; 
  lu_byte marked; 
  
  lu_byte nupvalues; 
  GCObject *gclist;
  struct Proto *p;
  UpVal *upvals[1];  /* list of upvalues */
} LClosure;


typedef union Closure {
  CClosure c;
  LClosure l;
} Closure;

// C

typedef struct UpVal {
  // collectable header
  struct GCObject *next; 
  lu_byte tt; 
  lu_byte marked;

  union {
    TValue *p;  /* points to stack or to its own value */
    ptrdiff_t offset;  /* used while the stack is being reallocated */
  } v;
  union {
    struct {  /* (when open) */
      struct UpVal *next;  /* linked list */
      struct UpVal **previous;
    } open;
    TValue value;  /* the value (when closed) */
  } u;
} UpVal;

// C

/*
** 'per thread' state
*/
struct lua_State {
  CommonHeader; // collectable object header
  lu_byte status;
  lu_byte allowhook;
  unsigned short nci;  /* number of items in call info list */
  StkIdRel top;  /* first free slot in the stack */
  global_State *l_G;
  CallInfo *ci;  /* call info for current function */
  StkIdRel stack_last;  /* end of stack (last element + 1) */
  StkIdRel stack;  /* stack base */
  UpVal *openupval;  /* list of open upvalues in this stack */
  StkIdRel tbclist;  /* list of to-be-closed variables */
  GCObject *gclist;
  struct lua_State *twups;  /* list of threads with open upvalues */
  struct lua_longjmp *errorJmp;  /* current error recover point */
  CallInfo base_ci;  /* CallInfo for first level (C calling Lua) */
  volatile lua_Hook hook;
  ptrdiff_t errfunc;  /* current error handling function (stack index) */
  l_uint32 nCcalls;  /* number of nested (non-yieldable | C)  calls */
  int oldpc;  /* last pc traced */
  int basehookcount;
  int hookcount;
  volatile l_signalT hookmask;
};