Example: Reversi (Othello)

Reversi uses an 8×8 grid, initial four discs in the center, and a PlaceNew move that must form a line (current space → existing disc of current player) with opponent discs in between; those get flipped (handled by the engine or follow-up moves).

Entities

• mainGrid — Grid 8×8.
• disc — Count Infinity, state includes player (set when placed).

initialPlacements put two discs of player 0 and two of player 1 in the four center cells.

Move

PlaceNew: entity is a disc with player from ctxPath currentPlayer. destination must be a Space, empty, and lie in an InLine sequence: (current space), then at least one opponent disc, then a disc of the current player (so the line is valid for flipping).

Turn has initialMoves with PassTurn when NoPossibleMoves.

End condition

Game ends when no moves possible; winner is determined by disc count (or similar logic in endIf with Evaluate / Every).

Full definition: server/examples/reversi.json, server/reversi2.json.