I found we can only maintain a single value on Lua stack, the only routine can maintain multi-values of lua stack is lua_settop(lua_pop). we can not:
- copy a range of stack to stack top (mult-version of lua_pushvalue)
- remove a range of stack (multi-version of lua_remove)
- insert multi value to middle of stack (multi-version of lua_insert)
- replace multi value to middle of stack (multi-version of lua_replace)
- copy multi values from a place to another (multi-version of lua_copy)
- copy multi values from a thread to another (copy-version of lua_xmove)
we needn't all these functions. only a few function is really needed, like:
- void lua_pushvalues(lua_State *L, int first, int last);
- void lua_removevalues(lua_State *L, int first, int last);
- void lua_xcopy(lua_State *from, lua_State *to, int n);
a multi-version of lua_remove is very most important -- to implement a proper vaeriosn of lua_removevalues need careful, a loop of lua_remove will cause O(n^2) behavior :-(
if we have lua_pushvalues, then lua_xcopy is not so important, now we can not push a range of lua value on stack, that need a loop, which is not convenience.
maybe Roberto can review this and add at least lua_pushvalues and lua_removevalues to Lua 5.3
thank you!
