Function treverse

src/ltablib.cpp:631–657

template <bool make_copy>
static int treverse (lua_State *L) {
  luaL_checktype(L, 1, LUA_TTABLE);

  if (make_copy) {
    lua_settop(L, 1);
    lua_newtable(L);
  }
  const lua_Unsigned l = lua_rawlen(L, 1);
  for (lua_Unsigned i = 1; i <= l/2; ++i) {
    lua_pushinteger(L, l - i + 1);
    lua_pushinteger(L, i);
    lua_rawget(L, 1);
    lua_pushinteger(L, i);
    lua_pushinteger(L, l - i + 1);
    lua_rawget(L, 1);
    lua_rawset(L, make_copy ? 2 : 1);
    lua_rawset(L, make_copy ? 2 : 1);
  }
  if (make_copy && (l % 2 != 0)) {
    /* for oddly sized tables, we need to manually copy the element in the middle */
    lua_pushinteger(L, l/2+1);
    lua_pushinteger(L, l/2+1);
    lua_rawget(L, 1);
    lua_rawset(L, 2);
  }
  return 1;
}


TValue *index2value (lua_State *L, int idx);