Documentation

A shot board records what has been learned about an opponent's board though shooting.

If one starts with the empty shot board, and then uses miss, hit and sank to record what is learned through shooting at a sequence of distinct positions of the opponent's board, then the shot board will remain consistent with the opponent's board.

No attempt is made to detect when a sequence of calls of miss, hit and sank doesn't correspond to an actual shooting history -- but the resulting shot board will be meaningless in such a case.

A cell of a shot board will either be:

• unshot;
• a miss -- shot, but not part of a ship;
• an unspecified hit -- shot, and part of an unknown (possibily shot) ship;
• a specified hit -- shot, and part of a specified, sunk ship.

In addition to the matrix of cells, the shot board records the possible locations of sunk ships: for each sunk ship, it is guaranteed that one of the recorded possibilities is correct.

A shot board in which all cells are unshot.

Mark a given cell as a miss; this doesn't change the record of possible locations of sunk ships.

Mark a given cell as an unspecified hit that didn't sink a ship; this doesn't change the record of possible locations of sunk ships.

Indicate that shooting at the specified position sank the specified ship. The position of the cell matrix is recorded as a hit of the ship, and the possible locations of the ship are added to the record of possible sunk ship locations.

Then a loop is run, in which:

• possible sunk ship locations that are inconsistent with the cell matrix are discarded;
• when only one possible location for a sunk ship remains, the matrix is updated so that the ship's cells are all specified hits for that ship.

Convert a shot board to a list of strings describing it. See MatrixUntrusted for the general format of the cell matrix. Cells are presented as follows:

• an unshot cell is presented as a space;
• a miss is presented as "*";
• an unspecified hit is presented as "+";
• a specified hit is presented as the uppercase version of the first letter of the ship's name.

The possible locations of sunk ships are described using the [a-z][a-z]:[h+v] notation.