ledger counter: Counter;

export circuit increment(): Uint<64> {
    counter.increment(1);
    return counter.value();
}

ledger balances: Map<Bytes<32>, Uint<64>>;

export circuit get_balance(user: Bytes<32>): Uint<64> {
    const result = balances.lookup(user);
    return if result is Maybe::Some(balance) { balance } else { 0 };
}

ledger members: MerkleTree<Bytes<32>>;

export circuit prove_membership(
    leaf: Bytes<32>,
    path: Vector<Bytes<32>, 20>
): Boolean {
    const computed_root = merkleTreePathRoot(leaf, path);
    return computed_root == members.root();
}