Bananagrams Competition

NB: GitHub has some incorrect rendering of org files, so not everything in this document will display correctly

Spec

The host

The program that manages the game and spawns the player processes.

It must behave fairly (specifics are determined by agreement of the players’ developers).

./host player1 player2 ... playern

# Each argument will be run verbatim in a sh-compatible shell, so: 
./host "ruby /path/to/a/ruby/player.rb" "/a/binary/player --some-argument"

Communication with the host

• Read stdin, write stdout.
• All printable ascii characters, no whitespace.

Unresolved issues

A race condition if a player peels before it is aware of another player’s peel.

Perhaps there should be sequence numbering, shared between all players, for peels. The server would need to ACK or NAK peels. And all of a sudden, the really simple host-to-player protocol is all complicated. Also, do we want to deal with more base-10 numbers, or should I give up on human-readability?

The protocol

In these examples:

• > shows player to host
• < shows host to player
• There are no whitespace characters

Initial communications

The player may perform arbitrary initialisation at process startup. When it is ready to play:

> r

Now the host may start the game by sending the player’s intial hand in alphabetical order (length determined by host, .-terminated).

< EEEGGKLOOPZ.

Peeling or winning the game

Send p followed by a grid:

> p003003ANDN..T..

All players will receive a new letter:

< R.

Dropping

Host response is in alphabetical order

> dQ
< AEZ.

Process termination

If the game is over, or the player has been determined by the host to have made a protocol error or an illegal move, the player shall be sent SIGTERM and must gracefully terminate.

<<Grid>>

The grid is the space in which a player builds their words. It is represented as follows:

xxxyyy[row_1][row_2]...[row_yyy]

Where:

• xxx and yyy are base-10 integers, comprising 3 ascii digits each, padded with leading zeroes if necessary
• xxx represents the width in columns of the grid
• yyy represents the height in rows of the grid
• [row_n] matches ^[A-Z.]{xxx}$, and represents a row of the grid, left-to-right, with a . representing a grid cell with no tile in it.
• The square brackets around [row_n] are for illustrative purposes and are illegal
• Empty rows and columns are legal

For example, 003005..AHERA.TT.YE.. is legal, contains the words “hate”, “her”, and “arty”, and could be visually represented as:

		A
H	E	R
A		T
T		Y
E

006007..........A...HER...A.T...T.Y...E......... is also legal and contains the same words in the same arrangment as above. It could be visually represented as:

				A
		H	E	R
		A		T
		T		Y
		E