mirror of https://github.com/janet-lang/janet
44 lines
1.0 KiB
Plaintext
44 lines
1.0 KiB
Plaintext
# A game of life implementation
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(def- window
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(seq [x :range [-1 2]
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y :range [-1 2]
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:when (not (and (zero? x) (zero? y)))]
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[x y]))
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(defn- neighbors
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[[x y]]
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(map (fn [[x1 y1]] [(+ x x1) (+ y y1)]) window))
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(defn tick
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"Get the next state in the Game Of Life."
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[state]
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(def cell-set (frequencies state))
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(def neighbor-set (frequencies (mapcat neighbors state)))
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(seq [coord :keys neighbor-set
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:let [count (get neighbor-set coord)]
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:when (or (= count 3) (and (get cell-set coord) (= count 2)))]
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coord))
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(defn draw
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"Draw cells in the game of life from (x1, y1) to (x2, y2)"
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[state x1 y1 x2 y2]
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(def cellset @{})
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(each cell state (put cellset cell true))
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(loop [x :range [x1 (+ 1 x2)]
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:after (print)
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y :range [y1 (+ 1 y2)]]
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(file/write stdout (if (get cellset [x y]) "X " ". ")))
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(print))
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#
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# Run the example
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#
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(var *state* '[(0 0) (-1 0) (1 0) (1 1) (0 2)])
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(for i 0 20
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(print "generation " i)
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(draw *state* -7 -7 7 7)
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(set *state* (tick *state*)))
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