gistfile1.perl

use Plack::App::Cascade;

my $app = Plack::App::Cascade->new;
$app->add(sub {
  my $env = shift;
  return sub {
    my $respond = shift;
    my $writer = $respond->([404, []]);
    $writer->write("boo");
    $writer->close;
  };
});

$app->add(sub {
  my $env = shift;
  return sub { 
    my $respond = shift;
    my $writer = $respond->([200,[]]);
    $writer->write("yay");
    $writer->close;
  }
});

$app->to_app;