program_00_good.pl

#!/usr/bin/env perl
# [[[ HEADER ]]]
use RPerl;
use strict;
use warnings;
our $VERSION = 0.001_000;

# [[[ CRITICS ]]]
## no critic qw(ProhibitUselessNoCritic ProhibitMagicNumbers RequireCheckedSyscalls)  # USER DEFAULT 1: allow numeric values & print operator
## no critic qw(RequireInterpolationOfMetachars)  # USER DEFAULT 2: allow single-quoted control characters & sigils

# [[[ OPERATIONS ]]]

my integer $foo = 3;
my integer $bar = -3;            # Literal Number, not Operator
my integer $bat = -(3);          # Operator(Literal Number)
my integer $baz = 5 - -($bar);

print 'have $foo = ', $foo, "\n";
print 'have $bar = ', $bar, "\n";
print 'have $bat = ', $bat, "\n";
print 'have $baz = ', $baz, "\n";

$foo = -(-3);                    # Operator(Literal Number)
$bar = -( -(3) );                # Operator(Operator(Literal Number))
$bat = $foo + -($bar);
$baz = $foo - -($bar);

print 'have $foo = ', $foo, "\n";
print 'have $bar = ', $bar, "\n";
print 'have $bat = ', $bat, "\n";
print 'have $baz = ', $baz, "\n";