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michael-simons/GoLEmbedded.java

Created October 15, 2025 08:27
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  1. michael-simons created this gist Oct 15, 2025.
    70 changes: 70 additions & 0 deletions GoLEmbedded.java
    View file
    Original file line number Diff line number Diff line change
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    ///usr/bin/env jbang "$0" "$@" ; exit $?
    //JAVA 25
    //RUNTIME_OPTIONS --enable-native-access=ALL-UNNAMED --add-opens=java.base/java.nio=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED --add-opens=java.base/sun.nio.ch=ALL-UNNAMED --add-opens=java.base/java.util.concurrent=ALL-UNNAMED
    //DEPS org.neo4j:neo4j:2025.09.0

    import org.neo4j.dbms.api.DatabaseManagementServiceBuilder;

    void main() throws IOException, InterruptedException {
    var height = 30;
    var width = 30;
    var sleep = Duration.ofMillis(500);

    var random = ThreadLocalRandom.current();
    var numAlive = (int) (height * width * 0.1);

    var cells = random.ints(numAlive * 2, 0, height).boxed().gather(Gatherers.windowSliding(2)).toList();

    try (var dbms = new DatabaseManagementServiceBuilder(Files.createTempDirectory("neo4j")).build()) {
    var db = dbms.database("neo4j");
    db.executeTransactionally("""
    UNWIND range(0,$height-1) AS row
    WITH row
    UNWIND range(0,$width-1) AS column
    WITH row, column
    CREATE (cell:Cell {coordinate: Point({x:column,y:row}), alive:false})
    WITH row, column, cell
    UNWIND [[row-1, column-1],[row-1, column],[row-1, column+1],[row, column-1]] AS neighbor
    MATCH (other:Cell {coordinate: Point({x:neighbor[1],y:neighbor[0]})})
    MERGE (other)-[:NEIGHBOUR_OF]->(cell)
    """, Map.of("height", height, "width", width));
    db.executeTransactionally("""
    UNWIND $cells AS cell
    MATCH (c:Cell {coordinate: Point({x:cell[0],y:cell[1]})})
    SET c.alive = true
    """, Map.of("cells", cells));

    var previous = "";
    while (true) {
    var result = db.executeTransactionally("""
    MATCH (cell:Cell)
    OPTIONAL MATCH (cell)-[:NEIGHBOUR_OF]-(:Cell {alive: true })
    WITH cell, COUNT(*) AS liveNeighbours
    SET cell.alive =
    CASE liveNeighbours
    WHEN <= 1 THEN FALSE
    WHEN >= 4 THEN FALSE
    WHEN = 3 THEN TRUE
    ELSE cell.alive
    END
    WITH cell ORDER BY cell.coordinate.y ASC, cell.coordinate.x ASC
    WITH collect(cell) AS cells
    RETURN reduce(res = "", cell IN cells | res +
    CASE cell.coordinate.x = 0 WHEN true THEN "\\n" ELSE "" END +
    CASE cell.alive
    WHEN true THEN '\u001b[1;38;5;0;48;5;253m ■ \u001b[0m'
    ELSE '\u001b[1;38;5;214;48;5;253m ■ \u001b[0m'
    END) AS result
    """, Map.of(), rows -> rows.next().get("result").toString());

    IO.print("\033[H\033[2J");
    IO.println(result);
    System.out.flush();
    Thread.sleep(sleep);
    if (result.equals(previous)) {
    break;
    }
    previous = result;
    }
    }
    }