Contracts are not necessarily only deployed by users, they can also be deployed by other contracts.
In this example, when pressing the Deploy button, we only deploy one contract instance - the one with constructor argument 1.
The second instance (with constructor argument 2) will be deployed by the first contract instance when it receives the deploy 2nd message. Send this message to the first instance by pressing the Send "deploy 2nd" to 1 button.
The combination of the inital code and the initial data of a contract is called the stateInit of the contract.
When sending any message to a contract, we can attach its stateInit by specifying the code and data fields of the message. This will deploy the contract if it has not already been deployed. If the contract has already been deployed, these fields will be ignored.
Notice that in this example, we piggyback the deployment on the indentify message.
import "@stdlib/deploy";
// we're going to have multiple instances of this contract, each with a different seqno
contract Todo with Deployable {
seqno: Int as uint64;
// when deploying an instance, we must specify its index (sequence number)
init(seqno: Int) {
self.seqno = seqno;
}
// each instance can calculate the address of every other instance
get fun addressOf(otherSeqno: Int): Address {
let init: StateInit = initOf Todo(otherSeqno);
return contractAddress(init);
}
}