access your caller's lexical underscore

 Starting with Perl 5.10, it is possible to create a lexical version of
 the Perl default variable $_. Certain Perl constructs like the "given"
 keyword automatically use a lexical $_ rather than the global $_.
 .
 It is occasionallly useful for a sub to be able to access its caller's
 $_ variable regardless of whether it was lexical or not. The "(_)" sub
 prototype is the official way to do so, however there are sometimes
 disadvantages to this; in particular it can only appear as the final
 required argument in a prototype, and there is no way of the sub
 differentiating between an explicitly passed argument and $_.
 .
 lexical::underscore allows you to access your caller's lexical $_
 variable as easily as:
 .
  ${lexical::underscore()}