Re: Lua <-> C++ integration with "unused" stack slots

[pan shizhu <pan.shizhu@...>]

> My intention with using the "unused stack slots" was to make it easy
> to write C++ code that uses some Lua objects without the need
> to manage stack indices manually.

But you generally should not use a C++ object to hold a Lua stack
value. If you write something to wrap the usage, you futher promoted
the abuse.


> LuaVar f(LuaVar x, const char* str)
> {
>   LuaVar rslt;
>   if (x.isTable()) {
>       LuaVar v = x[str];
>       rslt = ...
>       ...
>   } else {
>       ...
>   }
>   return rslt;
> }
>
> int main(int argc, char** argv)
> {
>    ...
>    LuaVar x = ...
>    ...
>    while (...) {
>        LuaVar y = f(x, argv[i])
>        if (y.isString()) {
>           ...
>        }
>    }
>    ...
> }


This should instead be:

> string f(map x, const char* str)
> {
>   string rslt;
>   if (x.isTable()) {
>       string v = x[str];
>       rslt = ...
>       ...
>   } else {
>       ...
>   }
>   return rslt;
> }
> int main(int argc, char** argv)
> {
>    ...
>    cppstring x = ...
>    ...
>    while (...) {
>        string y = f(x, argv[i])
>        if (y) {
>           ...
>        }
>    }
>    ...
> }

It is better to only use lua stack variable within one function, pass
lua stack value between c functions are dangerous and result in
difficult-to-maintain code.

A program which contains only standard C++ class, and a program which
contains lot's of lua private classes. What is more readable?

You're introducing the Python way of embed, and that reduces the
readibility of source code more than improvement.