Re: Lua's symbol table

[Thatcher Ulrich <tu@...>]

On Sun, 5 Aug 2001, Edgar Toernig wrote:

> > OK, I think I get this pretty well.  Although if I want to keep that char*
> > valid, it doesn't appear that Lua makes any guarantees, other than that
> > lua_getref() on the locked reference will still push a valid string.  It
> > seems as though the garbage collector is (and should be) still free to
> > move the actual data around.
>
> As I said, this property is not documented but in all versions of Lua
> I know (3.x, 4.x) the pointer stays the same until there's no longer
> a reference to it.  Lua's garbage collector does not move data around.
>
> IMHO if you embed Lua into some application you can make use of this
> property.  But if you want to take future memory management changes
> into account...

Yeah, this is something I don't want to have to think about when
upgrading.  As you and lhf suggest I'll just make my own symbol table
using a Lua table, mapping new symbols to an incrementing counter.  I
think that solves most of the problems.  For returning the symbol name
I'll probably return a C++ string to avoid worrying about Lua's gc.  That
operation is not too crucial anyway.

Thanks for the help,

-Thatcher