Re: Questions and remarks on draft-ietf-sieve-include-01.txt

[Aaron Stone <aaron@xxxxxxxxxxxxxx>]

On Tue, 05 May 2009 15:25:17 -0400, Jeffrey Hutzelman <jhutz@xxxxxxx>
wrote:
> --On Tuesday, May 05, 2009 11:07:59 AM +0200 Stephan Bosch 
> <stephan@xxxxxxxxxxxx> wrote:
> 
>> Also, you completely lifted the global command's placement requirements.
>> I am not fundamentally opposed to this, but this can make the inclusion
>> of a global variable conditional, i.e. inside an if statement. Until I
>> actually implement this I won't really know for sure whether there will
>> be implementation issues.
>>
>> And if the possibility for a conditional global command is desired, I
>> would expect an explicit mention of this possibility somewhere in the
>> command explanation. Now it could come to a surprise to the more naive
>> implementer. This also implies that a global variable is not included
>> into the local scope until after the first global command that specifies
>> it.
> 
> 
> I would expect that a global command has effect only from the command to 
> the end of the enclosing scope; as a result, a global inside a
conditional 
> has effect only on the conditional code, and never on something occurring

> after the conditional, regardless of whether the conditional is taken.

Would require variable scoping rules that follow the curly braces, but
we're doing it PHP / Python style in Sieve.

> Alternately, a global command could be defined to apply to the entire
file 
> regardless of where it occurs.

That presumes pre-parsing the script, which I don't want to sneakily make a
requirement of interpreters.

I went with this approach: the variable is local to the immediate script
until it is called global at some point later in the script. I flipped a
coin, and decided the local value would then overwrite the global value. I
could as easily see it go the other way, though. I can't think of any
particularly good examples from other languages that might apply here.
Feedback appreciated!

Aaron