But, when VALm is mapped to VALn and VALn is not a number, the
mapping proceed as below:
- If VALn is nil, the lastest map is ignored and the mapping of VALm
+ If VALn is nil, the last map is ignored and the mapping of VALm
proceed to the next map.
In VALn is t, VALm is reverted to reg[rrr] and the mapping of VALm