Accessing "internal" calls

[julien51]

When building a subgraph, we sometimes use the value passed to the transaction using event.transaction.value if event is an event emitted in a function. Unfortunately, that value refers to the "outer" transaction, not necessarily to the value passed to the function call.

It would be pretty useful to access the "internal" call from an event (i.e. the calldata + value) passed to the function that triggered the event.

This could be for example done by adding a call to the class Event, like this:

class Event {
  address: Address
  logIndex: BigInt
  transactionLogIndex: BigInt
  logType: string | null
  block: Block
  transaction: Transaction
  parameters: Array<EventParam>
  receipt: TransactionReceipt | null
  call: Call
}

where Call could be something like

class Call {
  value: BigInt
  data: Bytes!
}

Being able to access the data could also be useful.