Re: function kidnapping

["John Belmonte" <jvb@...>]

tomas@ccpa.puc-rio.br wrote:

> >     -- Assuming tag methods in place to allow swapping of global table
via
> >     -- a function "setglobaltable".
> >     function wrapper(func, ...)
> >         local oldtable = setglobaltable(t)
> >         local val = call(func, arg)
> >         setglobaltable(oldtable)
> >         return val
> >     end
>
> With this wrapper, when you swap the global table you'll loose
> (while executing the function, of course) all global functions, like
> print, gsub, write etc.  I think it would be better not to change the
> global environment but to check if the global exists.  If it doesn't,
> so try the local value.

Of course that depends on how you implement the tagmethods ("getglobal",
etc).  Probably you would have them search in t first, and if it isn't there
use rawgetglobal().  Or maybe when the namespace system is initialized copy
all "system globals" to a special namespace called std (I'm thinking of ANSI
C++ with the "std" namespace enabled).  Then all accesses to system globals
must be explicit, for example std.print().  (This will break if system
functions need to call eachother.)  A "using" could be implemented to open
up namespaces.  There are a lot of options.

Using the name setglobaltable() was probably misleading....  but I said
"roughly" ;)

-John