(yes, 2 years later in violation of #3 
)
Is “-” acting as a catch-all? Do we really need it in a map xformation file?
I will try to dig into the code to see if there is a reference to this.
For sure we need NULL (not null) for a possible state value but I am not sure about -
I usually use at the end of all of my *.map files the following:
-=OK
.=Uknown
NULL=Welcome to the Void!
but this is due to my ignorance 