###### renaming
# default range
c : 10
# one-element range
c 10: +10    
c 11:  21
# complete range
c 30 -- 39 : +100
c 40 -- 50 :  200
c 40 -- 50 :        # empty rule


####### changing
# default range
c : tmp 1e-8
# one-element range
c 10: imp:n 5.0 u=0
c 20: fill=5
# complete range
c 40 -- 50: mat 10 den -7.0


