#!/usr/bin/perl -w

use strict;
use warnings;
use HTML::Entities;

sub sanitize {
    # no name?
    $_[0] ||= "anonymous";

    # add missing protocol in $url
    if ($_[1] && $_[1] !~ /^\w+:/) {
        $_[1] = "http://" . $_[1]
    }

    # add missing protocol in link in $body
    $_[2] =~ s{\[(.*?)\]}{
        my $x = $1;
        if ($1 !~ /^\w+:/) {
            if ($1 =~ /\@/) {
                "[mailto:$x|$x]";
            } else {
                "[http://$x]"
            }
        } else {
            "[$x]"
        }
    }gex;

    # don't let people put in html
    $_[2] = HTML::Entities::encode($_[2]);
}

my $body = "Mail me at [bugs\@microsoft.com].";
my $url;
my $name;
sanitize("", $url, $body);

print $body, "\n";
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Modification of a read-only value attempted at 
perl-alias.pl line 9.