Re: Include 04 export/import

["Aaron Stone" <[e-mail]>]

On Wed, Jun 14, 2006, Kjetil Torgrim Homme <[e-mail]> said:

> [VARIABLES] says:
> 
>     Unknown variables are replaced by the empty string.
> 
> it's not an error.

Thanks, I was looking for that reference. I grepped for "undefined" and
"undeclared" and "unset" -- "unknown" was not the word I expected :-P

>> An included script could pull in more variables than were exported, and
>> simply find that some of them are not defined. For example, a :global
>> script might have some documented functionality like, "export ${this}
>> for some useful behavior, and ${that} for some other useful stuff." A
>> user might only set ${that}, but the script has imported both ${this}
>> and ${that}. I don't think it should cause an error.
> 
> I agree.
> 
>    If an "import" command lists a variable that has not been exported
>    and set by any other script at that point during the SIEVE execution
>    process, then an error MUST occur.
> 
> I suggest that "and set" is removed.  remember that changes made to the
> imported variable will be visible in the parent.  this is how values are
> returned from "calling" sub-scripts, and it would be strange to require
> the parent to set it prior to the call.  this should probably made clear
> in the draft.

Would a read-only modified be useful here? For example:

    export :readonly "testvar"

Also, would you still want to consider it an error to import a variable
that was not already exported? I'm on the fence about this.

Aaron