Concept Translation Tables

contract Token {
    mapping(address => uint256) balances;

    function transfer(address to, uint256 amount) public {
        balances[msg.sender] -= amount;  // Mutate in place
        balances[to] += amount;
    }
}

template Token
  with
    owner : Party
    amount : Decimal
  where
    signatory owner

    choice Transfer : ContractId Token
      with newOwner : Party
      controller owner
      do
        -- Archive this contract (implicit)
        -- Create new contract with new owner
        create this with owner = newOwner

function transfer(address to, uint256 amount) public {
    require(msg.sender == owner, "Not authorized");
    // ... transfer logic
}

choice Transfer : ContractId Asset
  controller owner  -- Only owner can exercise this choice
  do
    -- No runtime check needed; protocol enforces
    create this with owner = newOwner