By what book?  It would seem to me that BNF for dtc is completely  
under our control and if we want to change it we can.  I understand  
that there is some correspondence to Open Firmware, but it seems that  
if its people are ok with the dts format changing that's a lot easier  
than implementing tons of support in dtc for features that cpp gives us.

What about just providing a way to escape them ? Something like \# would
do the trick

Ben