Re: [Flightgear-devel] Snow line based on METAR

[Vivian M. <viv...@li...>]

Csaba wrote:

> -----Original Message-----
> From: Halász [mailto:csa...@gm...]
> Sent: 06 December 2011 16:55
> To: FlightGear developers discussions
> Subject: Re: [Flightgear-devel] Snow line based on METAR
> 
> On Tue, Dec 6, 2011 at 5:15 PM, Gijs de Rooy <gij...@ho...> wrote:
> >
> > I wrote a Nasal script, everything works fine, but I stumble accross a
> > problem with my listener. For
> > some reason the snow-cover property seems to be tied and therefore it
> always
> > reports "nil" to a
> > listener (AndersG said so, I got no idea what that means).
> >
> > Would it be possible to untie the prop? Or is there a better solution?
> You
> > can find the script below.
> 
> You can attach the listener to the metar/valid node which is left
> untied for this exact purpose. Make sure you trigger for all writes,
> not just changes (to catch valid->valid updates).
> 

I'm not sure that this is correct. Nasal listeners don't mind if a property
is tied or not - this must be true or else weather-utility.nas wouldn't work
to "untie" properties for use by effects. Effects use c++ listeners, and
these do care if a property is tied.

Vivian