CONDITION and ACTION;
[download]

E.g the code I've used for ages for flexible switch parsing, as the original simple arg handling module went against my tastes:

# maybe replace @ARGV below with my(@A)=@ARGV or similar, as we destro
+y the array
while($_=$ARGV[0]){
   /^(-V|-?-verbose)$/o  and do{shift; $verbose=1; ...; next};
   /^(-v|-?-negate)$/o   and do{shift; $negate=1;  ...; next};
   ...
   /^--?$/o              and do{shift;             ...; last}; # early
+ loop exit
   last;
}
[download]

Update 1:

Considering Bloodnok's variant below:

If your Perl's sufficiently recent, use my($_) instead of local to protect your caller while also protecting from anything called functions might do.

Also note that I'm using both next and last (loop exit condition) above. If you want a stronger distinction between looping and switching while retaining early loop exiting, you need either a second target label before the while() or set an explicit loop-exit flag variable for testing after the switch block. Simply saying last SWITCH in case of -- when restructuring does introduce a bug and changes semantics of -- to a NOP, with additional problems further down the line for non-option args.

Footnotes to my example above:

• For a cleaner syntax, you can use for my $_ (@ARGV) instead of the while if your loop nevers needs to access/eat multiple array members per iteration.
  But don't attempt the parens you normally should use with local, my and our: for my($_) (@ARGV)... will fail.
• To fall through, you can either set $_ suitably or unshift one or more values.
• Note the structural similarity of the lines above to, say, the suggestions in the mass pattern matching thread (->qr//, closures) or dispatch table methods (e.g. removing next, saying last whileloop depending on method-rc, and assuming NOP as default method)

Non-famous last words: I simply prefer the above solution over given/when and if-cascades for readability and perceived elegance. But given the ascii art readjustment and byte counts, it's not faster to maintain nor that much shorter.

Whilst your code self-evidently works, it doesn't satisfy the general case (pun intended) since it will only work within a loop - with modifications, it can be made to work anywhere.

The modifications involves the enclosing of the condiitons and actions inside a labelled block and reworking the next statements e.g.

while ($_ = $ARGV[0]) {
   SWITCH:
   {
      /^(-V|-?-verbose)$/o  and do{shift; $verbose=1; ...; last SWITCH
+};
      /^(-v|-?-negate)$/o   and do{shift; $negate=1;  ...; last SWITCH
+};
      ...
      /^--?$/o              and do{shift;             ...; last SWITCH
+};
   }
}
[download]

Also, personally, I would rewrite it as follows

PARSE:
while (@ARGV) {
   local $_ = shift;

   SWITCH:
   {
      /^(-V|-?-verbose)$/o  and do { $verbose=1; ...; last SWITCH };
      /^(-v|-?-negate)$/o   and do { $negate=1;  ...; last SWITCH };
      ...
      /^--?$/o              and do {             ...; last PARSE };
   }
}
[download]

Update:

Added correct loop termination (using PARSE label) for specific instance offered above.

A user level that continues to overstate my experience :-))

print $/;
[download]

[keszler@tek perl]# cat test3.pl
#!/usr/bin/perl -w

use Benchmark;
use strict;

my $results = timethese( 1e4, {
  a => sub{print "\n" for(1..1e4);},
  b => sub{print $/ for(1..1e4);},
} );

my $results2 = timethese( 1e4, {
  a2 => sub{print $/ for(1..1e4);},
  b2 => sub{print "\n" for(1..1e4);},
} );
[keszler@tek perl]# ./test3.pl | grep -v '^$'
Benchmark: timing 10000 iterations of a, b...
         a: 54 wallclock secs (33.83 usr +  0.92 sys = 34.75 CPU) @ 28
+7.77/s (n=10000)
         b: 54 wallclock secs (34.21 usr +  0.96 sys = 35.17 CPU) @ 28
+4.33/s (n=10000)
Benchmark: timing 10000 iterations of a2, b2...
        a2: 54 wallclock secs (34.37 usr +  0.93 sys = 35.30 CPU) @ 28
+3.29/s (n=10000)
        b2: 54 wallclock secs (33.69 usr +  0.90 sys = 34.59 CPU) @ 28
+9.10/s (n=10000)
[download]

And very, very slightly slower:

You just benchmarked I/O; you're not going to get meaningful results here.

I don't know how to get rid of given, but you could make it look a little less redundant:

while (1) {
    given (<>) {
        when (…) {…}
        default { last }
    }
}
[download]

do {
    given (<>) {
        when (…) {…}
        default { last }
    }
} while 1;
[download]

As others have observed, say '' is the same as print "\n". Have you thought about whether setting $\ will fulfil your needs?

Altho the given-when thing is cool, it would be cooler if the given() could be left out.

It can. given just sets $_, and the outer while-loop does that already, so it's really redundant.

And, by the way, is there an even shorter way to do print "\n"; ?

say.

No, it can't. You get error Can't use when() outside a topicalizer (5.10.1).

I tested it with a for loop, which works. The difference seems to be that while doesn't limit the scope of $_ in any way.

And say prints $_, doesn't it?

And say prints $_, doesn't it?

Do you see any mention of $_ in The Fine Manual? I don't. If you don't believe the documentation, you could always write your own code to answer your own question.