Extend last to accept labels

last already accepts labels.

implement "post loop switch"

That's horrible. Noone uses continue since it doesn't give access to the lexical vars of the loop, and this suffers from the same problem.

See Donald Knuth Structured Programming with go to Statements programming with goto statements

Perl already has a goto statement.

That said, while I use goto regularly in C, there's no reason to use it in Perl.