Re: Garbage Collector

["Leandro Candido" <enclle@...>]

Hello all,

This is a code for catchglobals:

-- begin code

function createo(n)
 local t = { n = n }, mt
 mt = { __gc = "gc" }
 setmetatable(t,mt)
 return t;
end

x = createo({})

function catchglobal( _function )
 local tab = {}
 local meta = {}
 local catched = {}
 function meta:__index( index )
   local c = catched
   local _G = _G
   local i = ( rawget(c,index) or 0 ) + 1;
   rawset(c,index,i);
   return _G[index];
 end
 function meta:__newindex( index, value )
   local c = catched
   local _G = _G;
   local i = ( rawget(c,index) or 0 ) + 1;
   rawset(c,index,i);
   _G[index] = value;
 end
 setmetatable(tab,meta);
 return function(...)
  local cat = catched;
  local env = tab;
  local func = _function;
  local oldenv = getfenv(_func);
  setfenv(func,env);
  local result = { func(unpack(arg)) }
  setfenv(func,oldenv);
  return cat, unpack(result);
 end
end

function test( HelloWorld )
 helloworld = HelloWorld;-- forget local keyword
 print(helloworld);
end

globalsvar = catchglobal ( test ) ("Hello World!")

print(type(globalsvar));
table.foreach(globalsvar,print);

globalsvar, result = catchglobal( createo ) ( {} );

table.foreach(globalsvar,print);

-- end code

    Please, add indentation, etc... to the code, because when pasting the
code it lost format.

                                                            The God's Peace,


Leandro.

----- Original Message -----
From: "Leandro Candido" <enclle@click21.com.br>
To: "Lua list" <lua@bazar2.conectiva.com.br>
Sent: Sunday, December 14, 2003 5:16 PM
Subject: Re: Garbage Collector


> Hello Edgar,
>
>     See below.
>
> ----- Original Message -----
> From: "Edgar Toernig" <froese@gmx.de>
> To: "Lua list" <lua@bazar2.conectiva.com.br>
> Sent: Sunday, December 14, 2003 1:12 PM
> Subject: Re: Garbage Collector
>
>
> > Nicolas Noble wrote:
> > >
> > > How exactly does the __gc metamethod works ? It just
> > > seems I'm not using it the right way.
> > >[...]
> > > function createobj(n)
> > >     local t = {n = n}, mt
> > >     mt = {__gc = mygc}
> > >     setmetatable(t, mt)
> > >     return t
> > > end
> >
> > The __gc method is only for userdata objects.  For other
> > types it's ignored.
> >
> > Btw, "local t = {n = n}, mt" looks wrong.
> >
> > Question: should Lua issue an error if there are
> >           more expressions than variable names?
> ...
>
>     Are you asking because the mt will be a global variable, and not a
> local?
>     If yes, I think the best is to modify lua to allow the local keyword
> work for ,XXX too. I always make this error, and always need to rewrite
the
> code.
>     If no, someone/you show me than what you are asking ;-).
>
>                                                     The God's Peace,
>
>
> Leandro.
>
>