Function luaV_finishset

depends/lua/src/lvm.c:203–238

** Finish a table assignment 't[key] = val'. ** If 'slot' is NULL, 't' is not a table. Otherwise, 'slot' points ** to the entry 't[key]', or to 'luaO_nilobject' if there is no such ** entry. (The value at 'slot' must be nil, otherwise 'luaV_fastset' ** would have done the job.) */

** would have done the job.)
*/
void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
                     StkId val, const TValue *slot) {
  int loop;  /* counter to avoid infinite loops */
  for (loop = 0; loop < MAXTAGLOOP; loop++) {
    const TValue *tm;  /* '__newindex' metamethod */
    if (slot != NULL) {  /* is 't' a table? */
      Table *h = hvalue(t);  /* save 't' table */
      lua_assert(ttisnil(slot));  /* old value must be nil */
      tm = fasttm(L, h->metatable, TM_NEWINDEX);  /* get metamethod */
      if (tm == NULL) {  /* no metamethod? */
        if (slot == luaO_nilobject)  /* no previous entry? */
          slot = luaH_newkey(L, h, key);  /* create one */
        /* no metamethod and (now) there is an entry with given key */
        setobj2t(L, cast(TValue *, slot), val);  /* set its new value */
        invalidateTMcache(h);
        luaC_barrierback(L, h, val);
        return;
      }
      /* else will try the metamethod */
    }
    else {  /* not a table; check metamethod */
      if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
        luaG_typeerror(L, t, "index");
    }
    /* try the metamethod */
    if (ttisfunction(tm)) {
      luaT_callTM(L, tm, t, key, val, 0);
      return;
    }
    t = tm;  /* else repeat assignment over 'tm' */
    if (luaV_fastset(L, t, key, slot, luaH_get, val))
      return;  /* done */
    /* else loop */
  }
  luaG_runerror(L, "'__newindex' chain too long; possible loop");
}


/*