Alpha ordinals are a way of providing "quick replies" for messaging services that do not support them natively, such as SMS and Whatsapp. With handle_message, they are supported directly.

Example

Imagine you send a user this reply:

What's your favorite color?
​
Reply with:
"A" for Red
"B" for Blue
"C" for Green
"D" for Yellow

The corresponding handle_message method would look like this:

def get_response
  handle_message(
    'Red' => proc { current_user.update_attributes!(favorite_color: 'red') },
    'Blue' => proc { current_user.update_attributes!(favorite_color: 'blue') },
    'Green' => proc { current_user.update_attributes!(favorite_color: 'green') },
    'Yellow' => proc { current_user.update_attributes!(favorite_color: 'yellow') }
  )
end

With alpha ordinals, if a user types "C", then the Green match arm is automatically selected since it is the 3rd match expression (Line 5) specified in handle_message. Similarly, the user could still reply with "green" directly and that will also match the 3rd match expression (Line 5).