我自认为的 Lua 5.3.4 主函数执行过程

int main (int argc, char **argv) {
  int status, result;
  lua_State *L = luaL_newstate();  /* create state */
  if (L == NULL) {
    l_message(argv[0], "cannot create state: not enough memory");
    return EXIT_FAILURE;
  }
  lua_pushcfunction(L, &pmain);  /* to call 'pmain' in protected mode */
  lua_pushinteger(L, argc);  /* 1st argument */
  lua_pushlightuserdata(L, argv); /* 2nd argument */
  status = lua_pcall(L, 2, 1, 0);  /* do the call */
  result = lua_toboolean(L, -1);  /* get result */
  report(L, status);
  lua_close(L);
  return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE;
}

LUALIB_API lua_State *luaL_newstate (void) {
  lua_State *L = lua_newstate(l_alloc, NULL);
  if (L) lua_atpanic(L, &panic);
  return L;
}

LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
  int i;
  lua_State *L;
  global_State *g;
  LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG)));
  if (l == NULL) return NULL;
  L = &l->l.l;
  g = &l->g;
  L->next = NULL;
  L->tt = LUA_TTHREAD;
  g->currentwhite = bitmask(WHITE0BIT);
  L->marked = luaC_white(g);
  preinit_thread(L, g);
  g->frealloc = f;
  g->ud = ud;
  g->mainthread = L;
  g->seed = makeseed(L);
  g->gcrunning = 0;  /* no GC while building state */
  g->GCestimate = 0;
  g->strt.size = g->strt.nuse = 0;
  g->strt.hash = NULL;
  setnilvalue(&g->l_registry);
  g->panic = NULL;
  g->version = NULL;
  g->gcstate = GCSpause;
  g->gckind = KGC_NORMAL;
  g->allgc = g->finobj = g->tobefnz = g->fixedgc = NULL;
  g->sweepgc = NULL;
  g->gray = g->grayagain = NULL;
  g->weak = g->ephemeron = g->allweak = NULL;
  g->twups = NULL;
  g->totalbytes = sizeof(LG);
  g->GCdebt = 0;
  g->gcfinnum = 0;
  g->gcpause = LUAI_GCPAUSE;
  g->gcstepmul = LUAI_GCMUL;
  for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL;
  if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) {
    /* memory allocation error: free partial state */
    close_state(L);
    L = NULL;
  }
  return L;
}

static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
  (void)ud; (void)osize;  /* not used */
  if (nsize == 0) {
    free(ptr);
    return NULL;
  }
  else
    return realloc(ptr, nsize);
}

/*
** Main thread combines a thread state and the global state
*/
typedef struct LG {
  LX l;
  global_State g;
} LG;

/*
** thread state + extra space
*/
typedef struct LX {
  lu_byte extra_[LUA_EXTRASPACE];
  lua_State l;
} LX;

/*
** 'global state', shared by all threads of this state
*/
typedef struct global_State {
  lua_Alloc frealloc;  /* function to reallocate memory */
  void *ud;         /* auxiliary data to 'frealloc' */
  l_mem totalbytes;  /* number of bytes currently allocated - GCdebt */
  l_mem GCdebt;  /* bytes allocated not yet compensated by the collector */
  lu_mem GCmemtrav;  /* memory traversed by the GC */
  lu_mem GCestimate;  /* an estimate of the non-garbage memory in use */
  stringtable strt;  /* hash table for strings */
  TValue l_registry;
  unsigned int seed;  /* randomized seed for hashes */
  lu_byte currentwhite;
  lu_byte gcstate;  /* state of garbage collector */
  lu_byte gckind;  /* kind of GC running */
  lu_byte gcrunning;  /* true if GC is running */
  GCObject *allgc;  /* list of all collectable objects */
  GCObject **sweepgc;  /* current position of sweep in list */
  GCObject *finobj;  /* list of collectable objects with finalizers */
  GCObject *gray;  /* list of gray objects */
  GCObject *grayagain;  /* list of objects to be traversed atomically */
  GCObject *weak;  /* list of tables with weak values */
  GCObject *ephemeron;  /* list of ephemeron tables (weak keys) */
  GCObject *allweak;  /* list of all-weak tables */
  GCObject *tobefnz;  /* list of userdata to be GC */
  GCObject *fixedgc;  /* list of objects not to be collected */
  struct lua_State *twups;  /* list of threads with open upvalues */
  unsigned int gcfinnum;  /* number of finalizers to call in each GC step */
  int gcpause;  /* size of pause between successive GCs */
  int gcstepmul;  /* GC 'granularity' */
  lua_CFunction panic;  /* to be called in unprotected errors */
  struct lua_State *mainthread;
  const lua_Number *version;  /* pointer to version number */
  TString *memerrmsg;  /* memory-error message */
  TString *tmname[TM_N];  /* array with tag-method names */
  struct Table *mt[LUA_NUMTAGS];  /* metatables for basic types */
  TString *strcache[STRCACHE_N][STRCACHE_M];  /* cache for strings in API */
} global_State;

/*
** 'per thread' state
*/
struct lua_State {
  CommonHeader;
  unsigned short nci;  /* number of items in 'ci' list */
  lu_byte status;
  StkId top;  /* first free slot in the stack */
  global_State *l_G;
  CallInfo *ci;  /* call info for current function */
  const Instruction *oldpc;  /* last pc traced */
  StkId stack_last;  /* last free slot in the stack */
  StkId stack;  /* stack base */
  UpVal *openupval;  /* list of open upvalues in this stack */
  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) */
  int stacksize;
  int basehookcount;
  int hookcount;
  unsigned short nny;  /* number of non-yieldable calls in stack */
  unsigned short nCcalls;  /* number of nested C calls */
  l_signalT hookmask;
  lu_byte allowhook;
};

/*
** Common Header for all collectable objects (in macro form, to be
** included in other objects)
*/
#define CommonHeader  GCObject *next; lu_byte tt; lu_byte marked

/*
** preinitialize a thread with consistent values without allocating
** any memory (to avoid errors)
*/
static void preinit_thread (lua_State *L, global_State *g) {
  G(L) = g;
  L->stack = NULL;
  L->ci = NULL;
  L->nci = 0;
  L->stacksize = 0;
  L->twups = L;  /* thread has no upvalues */
  L->errorJmp = NULL;
  L->nCcalls = 0;
  L->hook = NULL;
  L->hookmask = 0;
  L->basehookcount = 0;
  L->allowhook = 1;
  resethookcount(L); // #define resethookcount(L) (L->hookcount = L->basehookcount) # ldebug.h#18
  L->openupval = NULL;
  L->nny = 1;
  L->status = LUA_OK;
  L->errfunc = 0;
}

int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
  unsigned short oldnCcalls = L->nCcalls;
  struct lua_longjmp lj;
  lj.status = LUA_OK;
  lj.previous = L->errorJmp;  /* chain new error handler */
  L->errorJmp = &lj;
  LUAI_TRY(L, &lj,
    (*f)(L, ud);
  );
  L->errorJmp = lj.previous;  /* restore old error handler */
  L->nCcalls = oldnCcalls;
  return lj.status;
}

/*
** open parts of the state that may cause memory-allocation errors.
** ('g->version' != NULL flags that the state was completely build)
*/
static void f_luaopen (lua_State *L, void *ud) {
  global_State *g = G(L);
  UNUSED(ud);
  stack_init(L, L);  /* init stack */
  init_registry(L, g);
  luaS_init(L);
  luaT_init(L);
  luaX_init(L);
  g->gcrunning = 1;  /* allow gc */
  g->version = lua_version(NULL);
  luai_userstateopen(L);
}

/* chain list of long jump buffers */
struct lua_longjmp {
  struct lua_longjmp *previous;
  luai_jmpbuf b;
  volatile int status;  /* error code */
};

#define LUAI_TRY(L,c,a)   if (setjmp((c)->b) == 0) { a }

static void stack_init (lua_State *L1, lua_State *L) {
  int i; CallInfo *ci;
  /* initialize stack array */
  L1->stack = luaM_newvector(L, BASIC_STACK_SIZE, TValue);
  L1->stacksize = BASIC_STACK_SIZE;
  for (i = 0; i < BASIC_STACK_SIZE; i++)
    setnilvalue(L1->stack + i);  /* erase new stack */
  L1->top = L1->stack;
  L1->stack_last = L1->stack + L1->stacksize - EXTRA_STACK;
  /* initialize first ci */
  ci = &L1->base_ci;
  ci->next = ci->previous = NULL;
  ci->callstatus = 0;
  ci->func = L1->top;
  setnilvalue(L1->top++);  /* 'function' entry for this 'ci' */
  ci->top = L1->top + LUA_MINSTACK;
  L1->ci = ci;
}

#define luaM_newvector(L,n,t) \
    cast(t *, luaM_reallocv(L, NULL, 0, n, sizeof(t)))

/*
** This macro reallocs a vector 'b' from 'on' to 'n' elements, where
** each element has size 'e'. In case of arithmetic overflow of the
** product 'n'*'e', it raises an error (calling 'luaM_toobig'). Because
** 'e' is always constant, it avoids the runtime division MAX_SIZET/(e).
**
** (The macro is somewhat complex to avoid warnings:  The 'sizeof'
** comparison avoids a runtime comparison when overflow cannot occur.
** The compiler should be able to optimize the real test by itself, but
** when it does it, it may give a warning about "comparison is always
** false due to limited range of data type"; the +1 tricks the compiler,
** avoiding this warning but also this optimization.)
*/
#define luaM_reallocv(L,b,on,n,e) \
  (((sizeof(n) >= sizeof(size_t) && cast(size_t, (n)) + 1 > MAX_SIZET/(e)) \
      ? luaM_toobig(L) : cast_void(0)) , \
   luaM_realloc_(L, (b), (on)*(e), (n)*(e)))

/*
** generic allocation routine.
*/
void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {
  void *newblock;
  global_State *g = G(L);
  size_t realosize = (block) ? osize : 0;
  lua_assert((realosize == 0) == (block == NULL));
#if defined(HARDMEMTESTS)
  if (nsize > realosize && g->gcrunning)
    luaC_fullgc(L, 1);  /* force a GC whenever possible */
#endif
  newblock = (*g->frealloc)(g->ud, block, osize, nsize);
  if (newblock == NULL && nsize > 0) {
    lua_assert(nsize > realosize);  /* cannot fail when shrinking a block */
    if (g->version) {  /* is state fully built? */
      luaC_fullgc(L, 1);  /* try to free some memory... */
      newblock = (*g->frealloc)(g->ud, block, osize, nsize);  /* try again */
    }
    if (newblock == NULL)
      luaD_throw(L, LUA_ERRMEM);
  }
  lua_assert((nsize == 0) == (newblock == NULL));
  g->GCdebt = (g->GCdebt + nsize) - realosize;
  return newblock;
}

/*
** Information about a call.
** When a thread yields, 'func' is adjusted to pretend that the
** top function has only the yielded values in its stack; in that
** case, the actual 'func' value is saved in field 'extra'.
** When a function calls another with a continuation, 'extra' keeps
** the function index so that, in case of errors, the continuation
** function can be called with the correct top.
*/
typedef struct CallInfo {
  StkId func;  /* function index in the stack */
  StkId top;  /* top for this function */
  struct CallInfo *previous, *next;  /* dynamic call link */
  union {
    struct {  /* only for Lua functions */
      StkId base;  /* base for this function */
      const Instruction *savedpc;
    } l;
    struct {  /* only for C functions */
      lua_KFunction k;  /* continuation in case of yields */
      ptrdiff_t old_errfunc;
      lua_KContext ctx;  /* context info. in case of yields */
    } c;
  } u;
  ptrdiff_t extra;
  short nresults;  /* expected number of results from this function */
  unsigned short callstatus;
} CallInfo;

/*
** Create registry table and its predefined values
*/
static void init_registry (lua_State *L, global_State *g) {
  TValue temp;
  /* create registry */
  Table *registry = luaH_new(L);
  sethvalue(L, &g->l_registry, registry);
  luaH_resize(L, registry, LUA_RIDX_LAST, 0);
  /* registry[LUA_RIDX_MAINTHREAD] = L */
  setthvalue(L, &temp, L);  /* temp = L */
  luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &temp);
  /* registry[LUA_RIDX_GLOBALS] = table of globals */
  sethvalue(L, &temp, luaH_new(L));  /* temp = new table (global table) */
  luaH_setint(L, registry, LUA_RIDX_GLOBALS, &temp);
}

Table *luaH_new (lua_State *L) {
  GCObject *o = luaC_newobj(L, LUA_TTABLE, sizeof(Table));
  Table *t = gco2t(o);
  t->metatable = NULL;
  t->flags = cast_byte(~0);
  t->array = NULL;
  t->sizearray = 0;
  setnodevector(L, t, 0);
  return t;
}

/*
** create a new collectable object (with given type and size) and link
** it to 'allgc' list.
*/
GCObject *luaC_newobj (lua_State *L, int tt, size_t sz) {
  global_State *g = G(L);
  GCObject *o = cast(GCObject *, luaM_newobject(L, novariant(tt), sz));
  o->marked = luaC_white(g);
  o->tt = tt;
  o->next = g->allgc;
  g->allgc = o;
  return o;
}

#define luaM_newobject(L,tag,s) luaM_realloc_(L, NULL, tag, (s))

/*
** Common type has only the common header
*/
struct GCObject {
  CommonHeader;
};

#define gco2t(o)  check_exp((o)->tt == LUA_TTABLE, &((cast_u(o))->h))

#define cast_u(o) cast(union GCUnion *, (o))

/*
** Union of all collectable objects (only for conversions)
*/
union GCUnion {
  GCObject gc;  /* common header */
  struct TString ts;
  struct Udata u;
  union Closure cl;
  struct Table h;
  struct Proto p;
  struct lua_State th;  /* thread */
};

typedef struct Table {
  CommonHeader;
  lu_byte flags;  /* 1<<p means tagmethod(p) is not present */
  lu_byte lsizenode;  /* log2 of size of 'node' array */
  unsigned int sizearray;  /* size of 'array' array */
  TValue *array;  /* array part */
  Node *node;
  Node *lastfree;  /* any free position is before this position */
  struct Table *metatable;
  GCObject *gclist;
} Table;

#define sethvalue(L,obj,x) \
  { TValue *io = (obj); Table *x_ = (x); \
    val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_TTABLE)); \
    checkliveness(L,io); }

void luaH_resize (lua_State *L, Table *t, unsigned int nasize,
                                          unsigned int nhsize) {
  unsigned int i;
  int j;
  unsigned int oldasize = t->sizearray;
  int oldhsize = allocsizenode(t);
  Node *nold = t->node;  /* save old hash ... */
  if (nasize > oldasize)  /* array part must grow? */
    setarrayvector(L, t, nasize);
  /* create new hash part with appropriate size */
  setnodevector(L, t, nhsize);
  if (nasize < oldasize) {  /* array part must shrink? */
    t->sizearray = nasize;
    /* re-insert elements from vanishing slice */
    for (i=nasize; i<oldasize; i++) {
      if (!ttisnil(&t->array[i]))
        luaH_setint(L, t, i + 1, &t->array[i]);
    }
    /* shrink array */
    luaM_reallocvector(L, t->array, oldasize, nasize, TValue);
  }
  /* re-insert elements from hash part */
  for (j = oldhsize - 1; j >= 0; j--) {
    Node *old = nold + j;
    if (!ttisnil(gval(old))) {
      /* doesn't need barrier/invalidate cache, as entry was
         already present in the table */
      setobjt2t(L, luaH_set(L, t, gkey(old)), gval(old));
    }
  }
  if (oldhsize > 0)  /* not the dummy node? */
    luaM_freearray(L, nold, cast(size_t, oldhsize)); /* free old hash */
}

/*
** Initialize the string table and the string cache
*/
void luaS_init (lua_State *L) {
  global_State *g = G(L);
  int i, j;
  luaS_resize(L, MINSTRTABSIZE);  /* initial size of string table */
  /* pre-create memory-error message */
  g->memerrmsg = luaS_newliteral(L, MEMERRMSG);
  luaC_fix(L, obj2gco(g->memerrmsg));  /* it should never be collected */
  for (i = 0; i < STRCACHE_N; i++)  /* fill cache with valid strings */
    for (j = 0; j < STRCACHE_M; j++)
      g->strcache[i][j] = g->memerrmsg;
}

void luaT_init (lua_State *L) {
  static const char *const luaT_eventname[] = {  /* ORDER TM */
    "__index", "__newindex",
    "__gc", "__mode", "__len", "__eq",
    "__add", "__sub", "__mul", "__mod", "__pow",
    "__div", "__idiv",
    "__band", "__bor", "__bxor", "__shl", "__shr",
    "__unm", "__bnot", "__lt", "__le",
    "__concat", "__call"
  };
  int i;
  for (i=0; i<TM_N; i++) {
    G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]);
    luaC_fix(L, obj2gco(G(L)->tmname[i]));  /* never collect these names */
  }
}

void luaX_init (lua_State *L) {
  int i;
  TString *e = luaS_newliteral(L, LUA_ENV);  /* create env name */
  luaC_fix(L, obj2gco(e));  /* never collect this name */
  for (i=0; i<NUM_RESERVED; i++) {
    TString *ts = luaS_new(L, luaX_tokens[i]);
    luaC_fix(L, obj2gco(ts));  /* reserved words are never collected */
    ts->extra = cast_byte(i+1);  /* reserved word */
  }
}

LUA_API const lua_Number *lua_version (lua_State *L) {
  static const lua_Number version = LUA_VERSION_NUM;
  if (L == NULL) return &version;
  else return G(L)->version;
}

/*
** these macros allow user-specific actions on threads when you defined
** LUAI_EXTRASPACE and need to do something extra when a thread is
** created/deleted/resumed/yielded.
*/
#if !defined(luai_userstateopen)
#define luai_userstateopen(L)   ((void)L)
#endif

LUA_API lua_CFunction lua_atpanic (lua_State *L, lua_CFunction panicf) {
  lua_CFunction old;
  lua_lock(L);
  old = G(L)->panic;
  G(L)->panic = panicf;
  lua_unlock(L);
  return old;
}

static int panic (lua_State *L) {
  lua_writestringerror("PANIC: unprotected error in call to Lua API (%s)\n",
                        lua_tostring(L, -1));
  return 0;  /* return to Lua to abort */
}

#define lua_pushcfunction(L,f)  lua_pushcclosure(L, (f), 0)

LUA_API void lua_pushcclosure (lua_State *L, lua_CFunction fn, int n) {
  lua_lock(L);
  if (n == 0) {
    setfvalue(L->top, fn);
  }
  else {
    CClosure *cl;
    api_checknelems(L, n);
    api_check(L, n <= MAXUPVAL, "upvalue index too large");
    cl = luaF_newCclosure(L, n);
    cl->f = fn;
    L->top -= n;
    while (n--) {
      setobj2n(L, &cl->upvalue[n], L->top + n);
      /* does not need barrier because closure is white */
    }
    setclCvalue(L, L->top, cl);
  }
  api_incr_top(L);
  luaC_checkGC(L);
  lua_unlock(L);
}

#define api_incr_top(L)   {L->top++; api_check(L, L->top <= L->ci->top, \
        "stack overflow");}

/* more often than not, 'pre'/'pos' are empty */
#define luaC_checkGC(L)   luaC_condGC(L,(void)0,(void)0)

/*
** Does one step of collection when debt becomes positive. 'pre'/'pos'
** allows some adjustments to be done only when needed. macro
** 'condchangemem' is used only for heavy tests (forcing a full
** GC cycle on every opportunity)
*/
#define luaC_condGC(L,pre,pos) \
  { if (G(L)->GCdebt > 0) { pre; luaC_step(L); pos;}; \
    condchangemem(L,pre,pos); }

/*
** performs a basic GC step when collector is running
*/
void luaC_step (lua_State *L) {
  global_State *g = G(L);
  l_mem debt = getdebt(g);  /* GC deficit (be paid now) */
  if (!g->gcrunning) {  /* not running? */
    luaE_setdebt(g, -GCSTEPSIZE * 10);  /* avoid being called too often */
    return;
  }
  do {  /* repeat until pause or enough "credit" (negative debt) */
    lu_mem work = singlestep(L);  /* perform one single step */
    debt -= work;
  } while (debt > -GCSTEPSIZE && g->gcstate != GCSpause);
  if (g->gcstate == GCSpause)
    setpause(g);  /* pause until next cycle */
  else {
    debt = (debt / g->gcstepmul) * STEPMULADJ;  /* convert 'work units' to Kb */
    luaE_setdebt(g, debt);
    runafewfinalizers(L);
  }
}

LUA_API void lua_pushinteger (lua_State *L, lua_Integer n) {
  lua_lock(L);
  setivalue(L->top, n);
  api_incr_top(L);
  lua_unlock(L);
}

LUA_API void lua_pushlightuserdata (lua_State *L, void *p) {
  lua_lock(L);
  setpvalue(L->top, p);
  api_incr_top(L);
  lua_unlock(L);
}

#define lua_pcall(L,n,r,f)  lua_pcallk(L, (n), (r), (f), 0, NULL)

LUA_API int lua_pcallk (lua_State *L, int nargs, int nresults, int errfunc,
                        lua_KContext ctx, lua_KFunction k) {
  struct CallS c;
  int status;
  ptrdiff_t func;
  lua_lock(L);
  api_check(L, k == NULL || !isLua(L->ci),
    "cannot use continuations inside hooks");
  api_checknelems(L, nargs+1);
  api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
  checkresults(L, nargs, nresults);
  if (errfunc == 0)
    func = 0;
  else {
    StkId o = index2addr(L, errfunc);
    api_checkstackindex(L, errfunc, o);
    func = savestack(L, o);
  }
  c.func = L->top - (nargs+1);  /* function to be called */
  if (k == NULL || L->nny > 0) {  /* no continuation or no yieldable? */
    c.nresults = nresults;  /* do a 'conventional' protected call */
    status = luaD_pcall(L, f_call, &c, savestack(L, c.func), func);
  }
  else {  /* prepare continuation (call is already protected by 'resume') */
    CallInfo *ci = L->ci;
    ci->u.c.k = k;  /* save continuation */
    ci->u.c.ctx = ctx;  /* save context */
    /* save information for error recovery */
    ci->extra = savestack(L, c.func);
    ci->u.c.old_errfunc = L->errfunc;
    L->errfunc = func;
    setoah(ci->callstatus, L->allowhook);  /* save value of 'allowhook' */
    ci->callstatus |= CIST_YPCALL;  /* function can do error recovery */
    luaD_call(L, c.func, nresults);  /* do the call */
    ci->callstatus &= ~CIST_YPCALL;
    L->errfunc = ci->u.c.old_errfunc;
    status = LUA_OK;  /* if it is here, there were no errors */
  }
  adjustresults(L, nresults);
  lua_unlock(L);
  return status;
}

#define api_checknelems(L,n)  api_check(L, (n) < (L->top - L->ci->func), \
          "not enough elements in the stack")

int luaD_pcall (lua_State *L, Pfunc func, void *u,
                ptrdiff_t old_top, ptrdiff_t ef) {
  int status;
  CallInfo *old_ci = L->ci;
  lu_byte old_allowhooks = L->allowhook;
  unsigned short old_nny = L->nny;
  ptrdiff_t old_errfunc = L->errfunc;
  L->errfunc = ef;
  status = luaD_rawrunprotected(L, func, u);
  if (status != LUA_OK) {  /* an error occurred? */
    StkId oldtop = restorestack(L, old_top);
    luaF_close(L, oldtop);  /* close possible pending closures */
    seterrorobj(L, status, oldtop);
    L->ci = old_ci;
    L->allowhook = old_allowhooks;
    L->nny = old_nny;
    luaD_shrinkstack(L);
  }
  L->errfunc = old_errfunc;
  return status;
}

/*
** Main body of stand-alone interpreter (to be called in protected mode).
** Reads the options and handles them all.
*/
static int pmain (lua_State *L) {
  int argc = (int)lua_tointeger(L, 1);
  char **argv = (char **)lua_touserdata(L, 2);
  int script;
  int args = collectargs(argv, &script);
  luaL_checkversion(L);  /* check that interpreter has correct version */
  if (argv[0] && argv[0][0]) progname = argv[0];
  if (args == has_error) {  /* bad arg? */
    print_usage(argv[script]);  /* 'script' has index of bad arg. */
    return 0;
  }
  if (args & has_v)  /* option '-v'? */
    print_version();
  if (args & has_E) {  /* option '-E'? */
    lua_pushboolean(L, 1);  /* signal for libraries to ignore env. vars. */
    lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
  }
  luaL_openlibs(L);  /* open standard libraries */
  createargtable(L, argv, argc, script);  /* create table 'arg' */
  if (!(args & has_E)) {  /* no option '-E'? */
    if (handle_luainit(L) != LUA_OK)  /* run LUA_INIT */
      return 0;  /* error running LUA_INIT */
  }
  if (!runargs(L, argv, script))  /* execute arguments -e and -l */
    return 0;  /* something failed */
  if (script < argc &&  /* execute main script (if there is one) */
      handle_script(L, argv + script) != LUA_OK)
    return 0;
  if (args & has_i)  /* -i option? */
    doREPL(L);  /* do read-eval-print loop */
  else if (script == argc && !(args & (has_e | has_v))) {  /* no arguments? */
    if (lua_stdin_is_tty()) {  /* running in interactive mode? */
      print_version();
      doREPL(L);  /* do read-eval-print loop */
    }
    else dofile(L, NULL);  /* executes stdin as a file */
  }
  lua_pushboolean(L, 1);  /* signal no errors */
  return 1;
}