Re: I-D ACTION:draft-daboo-sieve-include-03.txt (fwd)

[Cyrus Daboo <[e-mail]>]

Hi Nigel,

--On August 26, 2005 2:44:29 PM +0100 Nigel Swinson 
<[e-mail]> wrote:

>> I don't think we need ":global", and it would be confusing to use.
>
> I consider PHP a very mature scripting language and I consider thier
> scoping rules very well thought out most likely very carefully discussed.
> After using the language for several years I haven't really found fault
> with them.  It make me think it's worth copying what they have done.  And
> thus:
>
> I think Aaron and I are suggesting:
>
> Set file scope variable
>     set "var" "Hello Kitty";
>
> Set global scope variable, where global affects all scripts that come
> into existance with the include spec     set :global "var" "Hello Kitty";
>
> Set local scope variable, where local affects the current and nested
> command block (filescope if not currently in a control block.)  (would
> doubt would ever be used)     set :local "var" "Hello Kitty";
>
> And Kjetil seems to disagree.  Anybody else out there have any opinions?

I do think the security concerns that Nigel brought up are valid. As such 
there does need to be a way for script authors to prevent their variables 
from being used either in an included script or by the scripts that include 
it. A simple solution to that would be a ":private" and ":public" scoping 
where ":private" means file scope only. The default is ":public" scope.

One thing with scoping that we also have to be concerned with is handling 
errors. What if a script attempts to use a ":private" variable from another 
script? Should that be a run-time or activation time error? Or should sieve 
do something sensible, e.g. make the new variable ":private" too? It would 
probably be better to have errors at activation time. In fact I would also 
suggest having warnings at activation time to warn of variables from one 
file being used in another, if the user wants to know about it.

-- 
Cyrus Daboo