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Building a Dice Game ​

This example demonstrates deterministic randomness, state, and events. It does not handle money.

Contract randomness is derived from public execution context. Anyone can reproduce it, so do not use this pattern for a value-bearing or adversarial lottery.

python
plays = Hash(default_value=0)
wins = Hash(default_value=0)

RollEvent = LogEvent(
    "Roll",
    {
        "player": indexed(str),
        "guess": int,
        "roll": int,
        "won": bool,
    },
)

@export
def play(guess: int):
    assert 1 <= guess <= 6, "Guess must be between 1 and 6"

    random.seed()
    roll = random.randint(1, 6)
    won = roll == guess

    plays[ctx.caller] += 1
    if won:
        wins[ctx.caller] += 1

    RollEvent({
        "player": ctx.caller,
        "guess": guess,
        "roll": roll,
        "won": won,
    })
    return {"roll": roll, "won": won}

@export
def stats(player: str):
    return {"plays": plays[player], "wins": wins[player]}

Test the input bounds, event data, and counter updates with ContractingClient. If an application needs unpredictable outcomes, use a reviewed oracle or commit-reveal design with an explicit threat model.