Re: Simple Lua for scripts

[Ben Sunshine-Hill <sneftel@...>]

That's accomplished with setfenv. 

On 8/22/05, Alain <alainm@pobox.com> wrote:
> 
> 
> Aaron Brown escreveu:
> > Alain wrote:
> >>I want to include Lua scripts in screen objects. My
> >>concern is that I want to limit accessibility to too many
> >>LUA commands, I want to limit the commands that he can
> >>use.
> >
> > If I understand what you're trying to do, it can be done
> > easily in stock Lua.  First use loadstring() to turn the
> > user's code into a function (this is where you catch any
> > syntax errors).  Then use setfenv() to keep the function
> > from accessing any dangerous globals.  This second step is
> > explained in section 14.3 of Programming in Lua:
> > <http://www.lua.org/pil/14.3.html>
> 
> Ok, that was very usefull information and I will probably use both. But
> what I intended is something more restrictive. I want a syntax checker
> that forbids access to many lua functions, just saying ok/notok. I am
> thinking of a lexical analysis with only minimal lua syntax or something
> like that...
> 
> The problem is that LUA is a powerfull language, and I don't want users
> with all that power because I am the one who will have to give support
> to the program. That means that if the user puts some statement in his
> script he can do more that was intended fot him to do.
> 

That's accomplished with setfenv. Just only put the safe functions in
the environment that is set for the function.

Ben