[Internal change] Decompose the game logic and API

[sotetsuk]

I believe that the API of Pgx is sufficiently general, but the optimal API varies depending on the use case. I would like to separate the implementation functions of each game's logic and the API, to make it easier for users to adjust to their preferred API.

For example,

• core.State -> core.EnvState, GameState
• Each game implements
  • step(game_state, action) -> game_state
  • legal_action_maks(game_state)
  • is_terminal(game_state)
  • observe(game_state)
  • terminal_value(game_state) ?

---

• go
  • [Go] Separate go specific attributes #1129
  • [Go] Extract game logic functions #1130
  • [Go] Move game logic to _src/games #1131
  • [Go] Refactor naming #1132
  • [Go] Add new logic class #1133
  • [Go] Use NamedTuple instead of dataclass #1134
• 2048
• animal shogi
• backgammon
• bridge bidding
• chess
  • [Chess] Separate Chess specific attributes #1226
  • [Chess] Extract game logic functions #1227
  • [Chess] Move game logic to _src/games #1228
  • [Chess] Add game class #1229
• connect four
  • [ConnectFour] Separate game specific attributes #1151
  • [ConnectFour] Separate game specific methods #1152
  • [ConnectFour] Extract games/connect_four.py #1153
• gardner chess
• hex
  • [Hex] Extract game specific attributes #1287
  • [Hex] Extract logic functions #1288
  • [Hex] Create Game class #1289
  • [Hex] Enhance terminal computation #1290
  • [Hex] Use _player_order  #1291
• kuhn poker
• leduc hold'em
• minatar
  • asterix
  • breakout
  • freeway
  • seaquest
  • space invaders
• othello
• shogi
  • [Shogi] Extract game specific attributes #1265
  • [Shogi] Extract logic functions #1269
  • [Shogi] Add Game class #1271
  • [Shogi] Unuse assets #1272
• sparrow mahjong
• tic tac toe
  • [TicTacToe] Separate TicTacToe specific attributes #1146
  • [TicTacToe] Split game specific methods #1148
  • [TicTacToe] Extract games/tic_tac_toe.py #1149

[carlosgmartin]

@sotetsuk How would this approach handle intermediate rewards?

[sotetsuk]

Sorry for the late response 🙏 It depends on the game.
In the case of Go, it looks like https://github.com/sotetsuk/pgx/blob/main/pgx/_src/games/go.py#L129

Note that this change is just a internal change and is supposed to give no effects to the current public API.