Vassili Bykov wrote:
> ... The concern that
> made me change it to :> was the similarity of ; and ;;. It may sound
> good from the logical point of view, in practice I'm afraid it can be
> a source of bugs. 

That's my concern also.

By the way, I just checked the ANSI syntax, and discovered that the $_ 
(underscore) character is also legal as the first character in an 
identifier (Somehow, I had wrongly developed the notion that it could 
not occur in the first position.)  So I no longer favor "_|" as the 
token for the pipe operator.