RE: How to undefine a function?

["Gyorgy Bozoki" <gbozoki@...>]

Thank you, Ashwin, I'll look into using new globals tables.

Gyorgy Bozoki

-----Original Message-----
From: lua-bounces@bazar2.conectiva.com.br
[mailto:lua-bounces@bazar2.conectiva.com.br] On Behalf Of Ashwin Hirschi
Sent: Saturday, August 09, 2003 22:35
To: Lua list
Subject: Re: How to undefine a function?


> Is there a way to learn what functions are defined when I call
> lua_dofile() / lua_dostring()? And using this information, is there a 
> way to programmatically undefine these functions?

Undefining functions is pretty straight-forward: simply assign nil to the
corresponding function names. So, something like "func1 = nil" undefines
function "func1".

To determine what functions were actually redefined in a particular chunk, it
might help to remember the global environment is actually a table. You can
iterate the table to see what's there, run the chunk, and then iterate the
globals table again to see what's changed.

Another approach would be to set up a new (empty) globals table that delegates
to your original environment [see the reference manual on how you can delegate
lookup from one table to another, using tag/meta-methods]. Running your code
would then set up its entries in the new globals table, enabling you to see
exactly what was changed.

Undefining all code from the first script in your example would thus simply
become a matter of setting up a new globals table for your next script (and
forgetting about the first one, obviously). I believe such a "sandbox"-approach
may well be what you're looking for.

I hope this helps.

Ashwin.