relation-get output is problematic

[William Reade]

On Wed, 2012-05-09 at 13:09 -0700, Gustavo Niemeyer wrote:
> My proposal is this:
> 
> - Let's make the default output for everything structured be YAML
> (e.g. relation-get -)
> - Things like juju-log must not output *anything* (it is/was outputting {})

+1

> Then, I'd also like to take the chance to propose an extension to
> relation-get to help people that are getting out of the
> 
>     if [ `relation-get some-bool` = True ]; then ...; fi
> 
> situation, that actually makes the charm interface depend on
> Python-specific value names, onto a much better version:
> 
>     if relation-get --test some-bool; then ...; fi

+1 in principle; but I'd like to be sure what counts as true or false.
Boolean false should clearly be false; values that are entirely missing
should also be false; and almost everything else should certainly be
true; but what about zero numbers and empty strings? I'm personally
comfortable with treating those as true, but there's a case to be made
either way...

Cheers
William