#!/local/bin/perl -w
use warnings;
use strict;

# Runs the sub reference in arg #1
sub Doit
{
&{$_[0]};
}

# Start of a big block - don't want to pollute
{
my $x = 777;
my $y = 222;

print "Initialized, what's the values?";
print " x = $x\n";
print " y = $y\n\n";

sub mysub
    {
    print "  Start of subroutine\n";
    print "    what's x? (forget y for now)\n";
    print "    x = $x\n\n";
    print "    Going to child block\n";
    print "     let's inspect the variables again:\n";
        {
        Doit( 
            sub { 
            print "x = $x\n\n"; 
            print "      y = $y\n\n"; } );
        }
    }
}
# Big Block 
mysub();