ChessFidgetYou call that chess?

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The itch

• Like to play chess

• Dislike losing so much

• Too much work to get good - (For me it would be a dangerous rabbit hole.)

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The scratch

• Write software to address personal shortcomings

• ChessFidget: a chess app I (currently) always beat

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Currently looks like thisIn lieu of a demo, I'll post code and (Mac) binaries

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Dev goals/guidelines• Design for dopamine, not skill

- E.g. no move history

• Computer mostly plays worse chess than I do - Currently random moves - That will get boring; see above re: dopamine

• META: Exercise in Swift and reasoning about code - NOT an exercise in chess programming or AI

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😬:Agonizing re: modeling• What are my objects? (Board, Piece, Move, ...)

• In how many places do "business rules" live? - E.g. MoveValidator and MoveGenerator - OTOH, might help with mutual unit-testing

• Sometimes the problem was a Swift difficulty - Extending Grid<T>, T is Piece? vs. T is Bool

• Sometimes the answer was a Swift feature - Type constraints?

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"Move" as struct+moveTypeenum MoveType { case resignation case plainMove case pawnTwoSquares case captureEnPassant case pawnPromotion(type: PromotionType) case castleKingSide case castleQueenSide } struct Move { let start: Square let end: Square let type: MoveType }

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Works fineawaitingHumanMoveInvalid move e1-g1: cannotCastleBecauseKingOrRookHasMovedd1-d2 (plainMove) played by White (Human)awaitingComputerMoveb8-d7 (plainMove) played by Black (Computer)awaitingHumanMovee1-c1 (castleQueenSide) played by White (Human)awaitingComputerMoved7-b6 (plainMove) played by Black (Computer)awaitingHumanMove

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"Move" as class hierarchyprotocol MoveProtocol { func updateBoard(_ board: Board) } /* The classes would be something like: Move: MoveProtocol Resignation MoveWithStart PawnTwoSquares

CastleKingSide CastleQueenSide MoveWithStartAndEnd PlainMove CaptureEnPassant PawnPromotion */

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😬:Swift overwhelm

• Building my mental model, esp. re: type system

• Finally past the squirmy phase! 😬➞😊 - New info now gets added to mental framework

• Maybe pairing would have helped?

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Thoughts about learning

• Know thy brain - Came to terms with my jumpy learning - Shlemiel the painter (stay tuned for blog post)

• Be aware when/how reach out to people

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Other thoughts• Wow do I suck at chess

• Does writing this app mean I'm a bully at heart?

• Am I weird for sensing uncanny illusion of intent? - Feels like it's capturing back "on purpose" - Feels intentional when it checks me - This despite knowing there is *zero* AI - WTF it played Fool's Mate

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Actual early test (Computer=Black)(manually recreated; wish I'd taken a screenshot)

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Next (current thinking)• Find a third-party library, add (weak) AI

• Distinguish between stalemate and checkmate

• Add keyboard input - Might help me learn algebraic notation

• Add multi-game play

• Move on to other project ideas

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