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

sub foo {
    my $code = shift;

    return <<"END_MSG";
Add the code
<$code>
END_MSG
}

my $code = <<'END_MSG';
line 1
line2
END_MSG

print "before calling\n";
print $code;

print "after calling\n";
print foo($code);

print "why blank line above?\n";

##</code><code>##

sub foo {
    my $code = shift;

    chomp $code;
    return <<"END_MSG";
Add the code
$code
END_MSG
}