io.flush () Equivalent to io.output():flush().

lua_pushstring[-0, +1, m] const char *lua_pushstring (lua_State *L, const char *s); Pushes the zero-terminated string pointed to by s onto the stack. Lua makes (or reuses) an internal copy of the given string, so the memory at s can be freed or reused immediately after the function returns. Returns a pointer to the internal copy of the string. If s is NULL, pushes nil and returns NULL.

utf8.len (s [, i [, j]])sijij

debug.setmetatable (value, table) Sets the metatable for the given value to the given table (which can be nil). Returns value.

luaL_loadbuffer[-0, +1, –] int luaL_loadbuffer (lua_State *L, const char *buff, size_t sz, const char *name); Equivalent to luaL_loadbufferx with mode equal to NULL.

luaL_checklstring[-0, +0, v] const char *luaL_checklstring (lua_State *L, int arg, size_t *l); Checks whether the function argument arg is a string and returns this string; if l is not NULL fills *l with the string's length. This function uses lua_tolstring to get its result, so all conversions and caveats of that function apply here.

luaL_optstring[-0, +0, v] const char *luaL_optstring (lua_State *L, int arg, const char *d); If the function argument arg is a string, returns this string. If this argument is absent or is nil, returns d. Otherwise, raises an error.

pairs (t) If t has a metamethod __pairs, calls it with t as argument and returns the first three results from the call. Otherwise, returns three values: the next function, the table t, and nil, so that the construction for k,v in pairs(t) do body end will iterate over all key–value pairs of table t. See function next for the caveats of modifying the table during its traversal.

luaL_typename[-0, +0, –] const char *luaL_typename (lua_State *L, int index); Returns the name of the type of the value at the given index.

lua_rawgeti[-0, +1, –] int lua_rawgeti (lua_State *L, int index, lua_Integer n); Pushes onto the stack the value t[n], where t is the table at the given index. The access is raw, that is, it does not invoke the __index metamethod. Returns the type of the pushed value.