Book Image

Solidity Programming Essentials

Book Image

Solidity Programming Essentials

Overview of this book

Solidity is a contract-oriented language whose syntax is highly influenced by JavaScript, and is designed to compile code for the Ethereum Virtual Machine. Solidity Programming Essentials will be your guide to understanding Solidity programming to build smart contracts for Ethereum and blockchain from ground-up. We begin with a brief run-through of blockchain, Ethereum, and their most important concepts or components. You will learn how to install all the necessary tools to write, test, and debug Solidity contracts on Ethereum. Then, you will explore the layout of a Solidity source file and work with the different data types. The next set of recipes will help you work with operators, control structures, and data structures while building your smart contracts. We take you through function calls, return types, function modifers, and recipes in object-oriented programming with Solidity. Learn all you can on event logging and exception handling, as well as testing and debugging smart contracts. By the end of this book, you will be able to write, deploy, and test smart contracts in Ethereum. This book will bring forth the essence of writing contracts using Solidity and also help you develop Solidity skills in no time.
Table of Contents (17 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

The view, constant, and pure functions


Solidity provides special modifiers for functions, such as view, pure, and constant. These are also known as state mutability attributes because they define the scope of changes allowed within the Ethereum global state. The purpose of these modifiers is similar to those discussed previously, but there are some small differences. This section will detail the use of these keywords.

Writing smart contract functions helps primarily with the following three activities:

  • Updating state variables
  • Reading state variables
  • Logic execution

The execution of functions and transactions costs gas and is not free of cost. Every transaction needs a specified amount of gas based on its execution and callers are responsible for supplying that gas for successful execution. This is true for transactions or for any activity that modifies the global state of Ethereum.

There are functions that are only responsible for reading and returning the state variable, and these are like property...