#!/usr/bin/perl

use strict;
use warnings;

use Sub::Identify;
use Sub::Install;

sub hello_world {
    my $from = shift || 'who?!';
    return "Hello World from " . $from;
}

sub decorate_h1 {
    my $sub     = shift;
    my $subname = Sub::Identify::sub_name( $sub );
    Sub::Install::reinstall_sub({
        code => sub { my @args = @_; return "<h1>" . $sub->(@args) . "</h1>" },
        as   => $subname,
    });
    return;
}

decorate_h1(\&hello_world);
print hello_world('Perl!'), "\n";