Conventions used

There are a number of text conventions used throughout this book.

Code in text: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles.

A block of code is set as follows:

pragma solidity ^0.8.0; contract MyContract {  uint256 public value = 10;  bool public isGreater = value > 5; }

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

contract BadAccessControl {    address public owner;
    constructor() {
        owner = tx.origin;
    }
    function sensitiveFunction() public {
        require(tx.origin == owner, "BadAccessControl: Not authorized");// Sensitive code
    }
}

Any command-line input or output is written as follows:

contract MultiSigWallet {    uint minApprovers;
    address payable dealProposer;
    address payable beneficiary;
    mapping (address => bool) approvedBy;
    mapping (address => bool) isApprover;
    uint approvalsNum;

Bold: Indicates a new term, an important word, or words that you see on screen. For instance, words in menus or dialog boxes appear in bold. Here is an example: “Once you’ve signed up for an Infura account, you can create a new project by clicking on the Create New Project button on the dashboard.”

Tips or important notes

Appear like this.