Ticket-in, ticket out (TITO) machines are used in casino slot machines to print out a slip of paper with a barcode indicating the amount of money represented. These can in turn be redeemed for cash at an automated kiosk.

The grammars are called slot grammars because they are organized around slots (grammatical relations) and rules for filling them. The parser works bottom-up and maintains, for each phrase being built up, a list called the available slots list, ASLOTS.