RE: protect a set in c (non-existing elements)

[Thijs Schreijer <thijs@...>]

> -----Original Message-----
> From: lua-l-bounces@lists.lua.org [mailto:lua-l-bounces@lists.lua.org] On
> Behalf Of Tomas Guisasola Gorham
> Sent: vrijdag 14 februari 2014 12:04
> To: Lua mailing list
> Subject: Re: protect a set in c (non-existing elements)
> 
>  	Hi Thijs
> 
> > In Lua I would simply protect a set with something like this;
> >
> > function protect(self)
> >  return setmetatable(self, {
> >    __index = function(self, key)
> >      return rawget(self,key) or error("Key '"..tostring(key).."' not
> found.",2)
> >    end})
> > end
> >
> > local set = protect({ a = 1 , b = 2 })
> >
> > print(set.a)
> > print(set.b)
> > print(set.c)  --> error
>  	I wouldn't call this a "protection", but anyway...
> 
> > I have a c module, for which I want to protect the module table itself
> like this (so a reusable function is not required, just a one-off). What is
> the recommended way of doing that? Probably someone did this before, but my
> google-foo failed to deliver. So any pointers to/or examples would be
> appreciated.
>  	Module tables are just like any other tables, so why can't you do the
> same you showed up here?  Or maybe I've missed something.
> 
>  	Regards,
>  		Tomás

Obviously you're right. But this is simple in Lua and a bit cumbersome in c. So my question was more on how others solved it; possibly including a lua file in the module that does it, or embedding lua code in c (tried to find an example, but couldn't find it)
What's the most elegant way of doing it?

Thijs