One place where perl's heavy use of implicit variables scores is in
quick one-liners from the command prompt. I think ruby would be more
appealing in that area if it had a switch that ran the following loop:

while gets
  print $_.instance_eval {
    ...
  }
end

This would generalise the existing technique of mixing a few String
methods like gsub and scan into Kernel and having them act implicitly on
$_.

martin