sub ErrorHandler(&) {
  my $block = shift;

  my $output = '';
  my $warnings = '';

  {
    local *STDOUT;
    tie *STDOUT, 'Some::Class::Collecting::The::Output', \$output;

    local $SIG{__WARN__} = sub {
      local $_ = shift;
      $warnings .= $_;
      $warnings .= "\n" unless (/\n$/);
    };

    eval {
      $block->();
    }
  }

  if ($@) {
    # handle the errors
  }
  elsif ($warnings) {
    # handle the warnings
  }
  else {
    print $output;
  }
}