[trans] - Model comments

[Gerard Lemson]

Hi Dave
> 
> So would the attached model be legal? This is a combination of my original
> model with the technique you (and also Mark in a private email from last
> week) illustrated. My own hope is for a model in which everything is a Mapping
> (except for the MapRef class). So you can use a compound mapping of any type
> where-ever you can use an atomic mapping, and vice-versa.
> 
This is legal indeed.
Gerard