Function db_getlocal

3rd/lua-5.4.3/src/ldblib.c:203–231

static int db_getlocal (lua_State *L) {
  int arg;
  lua_State *L1 = getthread(L, &arg);
  int nvar = (int)luaL_checkinteger(L, arg + 2);  /* local-variable index */
  if (lua_isfunction(L, arg + 1)) {  /* function argument? */
    lua_pushvalue(L, arg + 1);  /* push function */
    lua_pushstring(L, lua_getlocal(L, NULL, nvar));  /* push local name */
    return 1;  /* return only name (there is no value) */
  }
  else {  /* stack-level argument */
    lua_Debug ar;
    const char *name;
    int level = (int)luaL_checkinteger(L, arg + 1);
    if (l_unlikely(!lua_getstack(L1, level, &ar)))  /* out of range? */
      return luaL_argerror(L, arg+1, "level out of range");
    checkstack(L, L1, 1);
    name = lua_getlocal(L1, &ar, nvar);
    if (name) {
      lua_xmove(L1, L, 1);  /* move local value */
      lua_pushstring(L, name);  /* push name */
      lua_rotate(L, -2, 1);  /* re-order */
      return 2;
    }
    else {
      luaL_pushfail(L);  /* no name (nor value) */
      return 1;
    }
  }
}


static int db_setlocal (lua_State *L) {