65 lines
1.4 KiB
FSharp
65 lines
1.4 KiB
FSharp
/// m02 model: the data the whole game is built from. Records and unions are immutable.
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module Snake.Model
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/// A grid cell. Records compare structurally: two points with the same X and Y are `=`.
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type Point = { X: int; Y: int }
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type Direction =
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| Up
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| Down
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| Left
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| Right
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type Status =
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| Playing
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| Paused
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| GameOver
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| Won
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/// Everything that can happen to the game, as data.
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type Action =
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| Tick
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| Turn of Direction
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| TogglePause
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| Restart
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| Frame
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/// The whole game. `Snake` is head first; `Seed` is the unsigned 32-bit random seed.
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type GameState =
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{ Width: int
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Height: int
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Snake: Point list
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Dir: Direction
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NextDir: Direction
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Apple: Point option
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Seed: uint32
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Score: int
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Status: Status
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Frame: int }
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let delta (dir: Direction) : Point =
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match dir with
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| Up -> { X = 0; Y = -1 }
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| Down -> { X = 0; Y = 1 }
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| Left -> { X = -1; Y = 0 }
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| Right -> { X = 1; Y = 0 }
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let opposite (dir: Direction) : Direction =
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match dir with
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| Up -> Down
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| Down -> Up
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| Left -> Right
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| Right -> Left
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let initialState (seed: uint32) : GameState =
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{ Width = 20
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Height = 20
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Snake = [ { X = 10; Y = 10 }; { X = 9; Y = 10 }; { X = 8; Y = 10 } ]
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Dir = Right
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NextDir = Right
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Apple = None
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Seed = seed
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Score = 0
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Status = Playing
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Frame = 0 }
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