Re: Garbage Collector

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

Hello all,

Only Minor info: replace rawget(c) and rawset(c) with normal c[x] and c[x]
=, because I use this code with a table with meta, but to send to the list I
replaced it with the "catched" table.

                                                                        God
bless you,


Leandro.

----- Original Message -----
From: "Leandro Candido" <enclle@click21.com.br>
To: "Lua list" <lua@bazar2.conectiva.com.br>
Sent: Sunday, December 14, 2003 5:32 PM
Subject: Re: Garbage Collector


> 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.
> >
> >
>
>