Santa’s Labyrinth

The inventory of tapes available to rent is small enough that it is impractical for visiting robots to guess arbitrary titles for rent, but large enough that it is impractical for the red clerk robot to list them all. The clerk will respond to queries that might help visitors select an appropriate movie.

Here are some example query exchanges for visitors asking about movies available at Big Value.

( ask for a recommendation of an arbitrary sword-and-sandal movie
   carried by the video store. Here we suppose the red robot
   broadcasts it's service with identifier "YOU" )
Q: [
    [X, "Alias", $X],
    [X, "Is", "Genre: Sword and Sandal"@"Movie Night"],
    [YOU, "Bid"@"Basic Relationships", X]
]
A: [
    [X, "Alias", "Odin the Conqueror (1984)"@"Movie Night"],
    [X, "Is", "Genre: Sword and Sandal"@"Movie Night"],
    [YOU, "Offers"@"Basic Relationships", X]
]

( ask for a better one )
Q: [
    [X, "Alias", $X],
    [X, "Is", "Genre: Sword and Sandal"@"Movie Night"],
    [X, "Is",  "Good"@"Basic Relationships"],
    [YOU, "Offers"@"Basic Relationships", X]
]
A: [
    [X, "Alias", "Clash of the Titans {1981)"],
    [X, "Is", "Genre: Sword and Sandal"@"Movie Night"],
    [X, "Is",  "Good"@"Basic Relationships"],
    [YOU, "Offers"@"Basic Relationships", X]
]

( ask for a recommendation for someone who
  also liked "Robocop (1987)" )
A: [
    ( the descriptive names for unbound objects
      are part of this human notation, but aren't
      part of the binary protocol )
    [Viewer, "Aliased", $X],
    [Movie, "Aliases", $Y],
    [Viewer, "Watch a Movie"@"Good Times", Movie],
    [Viewer, "Watch a Movie"@"Good Times", "Robocop (1987)"@"Movie Night"],
    [YOU, "Offers"@"Basic Relationships", X]
]
Q: [
    ( the reply to the query will use an actual identifier
      for a concrete viewer, but in many or most cases it will not be
      useful to the querent )
    [Viewer, "Aliased", <ARBITRARY IDENTIFIER>],
    [Movie, "Aliases", "Starship Troopers (1997)"@Movie Night"],
    [Viewer, "Watch a Movie"@"Good Times", Movie],
    [Viewer, "Watch a Movie"@"Good Times", "Robocop (1987)"@"Movie Night"],
    [YOU, "Offers"@"Basic Relationships", X]
]