Re: Globals (more ruminations)

[Ricardo Ramos Massaro <ricardo.massaro@...>]

On Fri, Jul 16, 2010 at 1:51 AM, Mark Hamburg <mark@grubmah.com> wrote:
> * "global a" as meaning that "a" should be interpreted as "_ENV.a" should be with respect to a specific definition of "_ENV". You may have already meant that, but I don't think you say so above. Which _ENV? My feeling is that it probably should tie to the chunk level _ENV, but I could be persuaded otherwise.
>
> * To preserve existing module construction practice, introducing a new _ENV should eliminate the checks on global assignments.

But what if a module writer *wants* the new check for his modules? In
Roberto's proposal, we can go from this:

 # -------
 local _ENV = module(...)
 global function set_x(new_x)
   xx = new_x  -- silent error: I meant "x" instead of "xx"
 end
 # -------

to this:

 # -------
 local _ENV = module(...)
 global x   -- declare x and enable checking
 global function set_x(new_x)
   xx = new_x  -- compiler error: attempt to assign to undeclared "xx"
 end
 # -------

-Ricardo