Optionally using Smart::Comments

Finally figured out how to turn Smart::Comments on and off as command line arguments:

shell> cat if.pl
#! /usr/bin/env perl

use 5.010_000;
use if 
    qr{\A -+ smart \z}ixms ~~ @ARGV,
    'Smart::Comments' => '####', '###';     

#### Going to sleep for intervals:
for ( 1 .. 5 ) { ### Speeping ...    [%] Done
  sleep 2;
}

exit 0;
shell> ./if.pl --smart

### Going to sleep for intervals:
Speeping ........        [50%] Done 

You can also get the same effect like so:

...
use if 
    $ENV{SMART},
    'Smart::Comments' => '####', '###';
...

shell> SMART=1 ./if.pl