Contrato que cria outros Contratos

Contratos podem ser criados por outros contratos usando a palavra-chave new. A partir da versão 0.8.0, a palavra-chave new suporta o recurso create2 por meio da especificação de opções salt.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.3;

contract Car {
    address public owner;
    string public model;
    address public carAddr;

    constructor(address _owner, string memory _model) payable {
        owner = _owner;
        model = _model;
        carAddr = address(this);
    }
}

contract CarFactory {
    Car[] public cars;

    function create(address _owner, string memory _model) public {
        Car car = new Car(_owner, _model);
        cars.push(car);
    }

    function createAndSendEther(address _owner, string memory _model) public payable {
        Car car = (new Car){value: msg.value}(_owner, _model);
        cars.push(car);
    }

    function create2(address _owner, string memory _model, bytes32 _salt) public {
        Car car = (new Car){salt: _salt}(_owner, _model);
        cars.push(car);
    }

    function create2AndSendEther(address _owner, string memory _model, bytes32 _salt) public payable {
        Car car = (new Car){value: msg.value, salt: _salt}(_owner, _model);
        cars.push(car);
    }

    function getCar(uint _index)
        public
        view
        returns (
            address owner,
            string memory model,
            address carAddr,
            uint balance
        )
    {
        Car car = cars[_index];

        return (car.owner(), car.model(), car.carAddr(), address(car).balance);
    }
}