Events

In Rubidity, events serve as mechanisms to log and emit changes or activities that occur within a smart contract. Here is how you can define and emit events in Rubidity.

Event Definition

To define an event in your Rubidity contract, you use the event keyword followed by the event name and a hash describing the expected arguments:

event :Transfer, { from: :addressOrDumbContract, to: :addressOrDumbContract, amount: :uint256 }

In this example, a Transfer event is defined with three arguments—from, to, and amount. Their types are also specified, making it strongly-typed just like any other aspect of Rubidity.

Event Emission

To emit an event, you call the emit method within your contract's methods. The emit method requires two arguments: the name of the event to emit and a hash containing the arguments to pass to the event:

def some_transfer_function(from, to, amount)
  # Perform transfer logic here
  emit(:Transfer, { from: from, to: to, amount: amount })
end

Event Validation

As with functions, Rubidity performs argument validation when emitting an event. Specifically, it checks:

• If the event is defined in the contract.

• If any required arguments are missing.

• If any unexpected arguments are included.

Example

Here is a small example that demonstrates defining and emitting an event in a Rubidity contract:

class Contracts::MyToken < Contract
  event :Transfer, { from: :address, to: :address, amount: :uint256 }
  
  function :do_transfer, { from: :address, to: :address, amount: :uint256 }, :public do
    # Perform the transfer logic here
    emit(:Transfer, { from: from, to: to, amount: amount })
  end
end