#!/usr/bin/perl
use strict;
use warnings;
use 5.012;
# 901284

my $count=0;
my $foo = "X x y y x y Z";

say "First, with a simple substitution '/g'";
my $simplecount = $foo =~ s/x/o/g;
say " \$foo: $foo; \n \$simplecount: $simplecount (i.e., 'x's changed)";
$foo =~ s/o/x/g;
say "\$foo restored: $foo \n";
say 'Now, with given/when and =~ /x/g';

given( $foo ) {
    when ( $foo =~ /x/g ) { 
       	say "\$foo contains an x"; 
		$count++; 
		say "\$foo: $foo; \n \$count: $count;";
		continue 
    }
    when ( /y/ ) {
       	say "\n \$foo contains a y"; 
    }
    default {
       	say "$foo does not contain a y"; 
    }
}
say "\n Final \$count of 'x' in given/when matching 'x': $count";

say "\n $foo";