Re: package.seeall and strict conflict

[David Manura <dm.lua@...>]

On Mon, Aug 17, 2009 at 4:29 PM, Jim Jennings wrote:
> On Thu, 13 Aug 2009 00:59:40 -0400, David Manura wrote:
>> Let some module A in a program do require "strict" and some other
>> module B in the program do module(..., package.seeall).  Now, strict
>> behavior is applied to the implementation of B.  This may be desirable
>> or it might not be.
>
> In my opinion, this is *not* desirable.  If A is written using
> "strict", then "strict" should apply only to A, and not to modules
> that use A.

I agree.  For example,

  require "strict" "globals"

where require "string" returns a function that when called updates the
environment of the caller (e.g. a private environment).

> If there is interest, I could find a place to post my implementation.
> (On Luaforge?)

I'm interested.  You may also post a page on the wiki (e.g. if you
feel it's not yet ready for LuaForge).

> But once you
> protect the metatable, you break a useful (and widely used) feature of
> Lua, which is the ability to change the metatable of the environment.

Though you can still change the environment (e.g. proxy the old environment).

> Here's a quick example using Lua Lanes 2.0.3, which I installed
> unmodified.  After playing with it, I wrote this declaration [3]:
>
>> structure.declare { name="lanes";
>                                 open={"_G", "package", "table", "string"};
>                                 environment=[[ require("lanes");
> return lanes ]];
>                               }
>> require "lanes"
>> dofile "lanes-test.lua"

What is the semantics of "open" ?  Does this add the listed symbols to
the private environment of the lanes module?