more fun with vW grammar

[WB Kloke]

> So where is the error? :)

Ok. Blind alleys won't produce programs. The problem i have with the COMMON
metanotion, is that alternatives starting with a mode cannot be made LL(1)
except the MODE can be outfactored.
For now, I just comment out such alternatives, in hope that the remaining
grammar is rich enough to be applied to a nontrivial program.

But, I would like to see a construct, for which this rule has been included.