🀄️ on swiftc

https://tryswift.jp/

1. @giginet
2. 🀄
3. Illustration by Nano Banana 2
4. Swift Compiler!
5. #expect(hand is Win) // ✅
6. खṛ Hand 14 Tiles
7. ੃಄ ໘ࢠ Head Melds ࿨ྃ Winning Hand
8. ࠁࢠ ॱࢠ Identical Meld Sequential Meld
9. struct Hand< H: AnyPair, M1: AnyMeld, M2: AnyMeld, M3: AnyMeld, M4: AnyMeld > {}
10. struct Pair< T1: TileType, T2: TileType >: AnyPair {} extension Pair: ValidPair where T1 == T2 {} struct Meld< T1: TileType, T2: TileType, T3: TileType >: AnyMeld {}
12. ᤈ<1>
13. SE-0452 Integer Generic Parameters
14. struct Tile<Suit: SuitType, let rank: Int>: TileType {} typealias ᤈ<let rank: Int> = Tile<ᤈࢠ, rank> typealias ౵<let rank: Int> = Tile<౵ࢠ, rank> typealias ࡧ<let rank: Int> = Tile<ࡧࢠ, rank> ᤈ<1> ࡧ<4> ౵<8> SE-0452 Integer Generic Parameters
15. extension Meld: ValidMeld where T1 == T2, T2 == T3 {}
16. #Playground { let identicalMeld = Meld<ᤈ<2>, ᤈ<2>, ᤈ<2>>() identicalMeld is ValidMeld } // ✅ true #Playground { let invalidMeld = Meld<ᤈ<2>, ౵<2>, ᤈ<3>>() invalidMeld is ValidMeld } // ❌ false
17. extension Meld: ValidMeld where Suit1 == Suit2, Suit2 == Suit3, rank1 + 1 == rank2, rank2 + 1 == rank3 {}
18. extension Meld: ValidMeld where Suit1 == Suit2, Suit2 == Suit3, rank1 + 1 == rank2, rank2 + 1 == rank3 {}
19. https://github.com/swiftlang/swift-evolution/blob/main/proposals/0452-integer-generic-parameters.md#future-directions
20. protocol Rank { associatedtype Next: Rank } struct One: Rank { typealias Next = Two } struct Two: Rank { typealias Next = Three } …
21. protocol Rank { associatedtype Next: Rank } struct `1`: Rank { typealias Next = `2` } struct `2`: Rank { typealias Next = `3` } … ᤈ<`1`> SE-0451 Raw Identi fi ers
22. extension Meld: ValidMeld where T1.S == T2.S, T2.S == T3.S, T1.R.Next == T2.R, T2.R.Next == T3.R {}
23. #Playground { let sequentialMeld = Meld<౵<`2`>, ౵<`3`>, ౵<`4`>>() sequentialMeld is ValidMeld } // ✅ true
24. extension Hand: Win where H: ValidPair, M1: ValidMeld, M2: ValidMeld, M3: ValidMeld, M4: ValidMeld {} #Playground { let hand = Hand< Pair<ᤈ<`1`>, ᤈ<`1`>>, Meld<ᤈ<`2`>, ᤈ<`3`>, ᤈ<`4`>>, Meld<౵<`5`>, ౵<`6`>, ౵<`7`>>, Meld<ࡧ<`3`>, ࡧ<`4`>, ࡧ<`5`>>, Meld<ࡧ<`7`>, ࡧ<`8`>, ࡧ<`9`>> >() hand is Win } // ✅ true
25. Union Type ࠁࢠ ॱࢠ type ValidMeld = IdenticalMeld | SequentialMeld
26. /// Identical Meld (ࠁࢠ) extension Meld: ValidMeld where T1 == T2, T2 == T3 {} /// Sequential Meld (ॱࢠ) extension Meld: ValidMeld where T1.S == T2.S, T2.S == T3.S, T1.R.Next == T2.R, T2.R.Next == T3.R {}
27. /// Identical Meld (ࠁࢠ) extension Meld: ValidMeld where T1 == T2, T2 == T3 {} /// Sequential Meld (ॱࢠ) extension Meld: ValidMeld where T1.S == T2.S, T2.S == T3.S, T1.R.Next == T2.R, T2.R.Next == T3.R {}
28. ❌ ❌ Union Types Arithmetic computation Can’t express sequential numbers with Integer Generics Parameters Can’t conform a protocol both identical and sequential states Pure Swift Type System limitations
29. SE-0382 Expression Macros
30. #Playground { let result = #validate([ ࡧ<4>(), ࡧ<4>(), ᤈ<2>(), ᤈ<3>(), ᤈ<4>(), ᤈ<5>(), ᤈ<6>(), ᤈ<7>(), ౵<3>(), ౵<4>(), ౵<5>(), ࡧ<6>(), ࡧ<7>(), ࡧ<8>() ]) result is Win } // ✅ true
31. @freestanding(expression) public macro validate(_ tiles: [14 of any Tile]) -> any Win = #externalMacro(module: "MacroValidatorMacros", type: "ValidateMacro") SE-0483 InlineArray Type Sugar SE-0382 Expression Macros
32. let win = #validate([ ࡧ<4>(), ࡧ<4>(), ᤈ<2>(), ᤈ<3>(), ᤈ<4>(), ᤈ<5>(), ᤈ<6>(), ᤈ<7>(), ౵<3>(), ౵<4>(), ౵<5>(), ࡧ<6>(), ࡧ<7>(), ࡧ<8>() ]) win is அϠΦ win is ฏ࿨ win is ରʑ࿨ // ✅ true // ✅ true // ❌ false
33. ✅ ✅ Winning Pattern detection Automatic Head/Meld grouping Macro can automatically group 14 tiles into head/melds Macro can detect Winning Patterns (໾) Expression Macros
34. Conclusion • Pure Swift Type System is powerful, but limited • Impossible to express complex game logics • Swift Macro is the Silver Bullet • Can represent the complex logic in the compilation time calculation
35. @giginet Thank you! https://mj-king.net/sozai/ Mahjong Tile Materials