[Solidity] 230215 study

Some contents of this article are based on Cryptozombies’s source code, based on GPL-3.0

Lesson 1

Chapter 1: Lesson Overview

Chapter 2: Contracts

• Solidity is encapsulated in contracts
• All solidity source should start with ‘version pragma’

Chapter 3: State Variables & Integers

• uint is normal, basic data type

Chapter 4: Math Operations

Chapter 5: Structs

Chapter 6: Arrays

• dataType[] pub/prv arrayName

Chapter 7: Function Declarations

• storing in memory
• by value, by reference

Chapter 8: Working With Structs and Arrays

• arrayName.push(proper_parameters)

Chapter 9: Pritvate / Public functions

• Function is set as public, by default
• however, it is good pratice to mark it as private
  • we should change it into public, when it needed
  • private function name starts with ‘_‘(underscore)

Chapter 10: More on Functions

• view / pure
• function mark 할 때, return이 아니라 returns다!

Chatper 11: Keccak256 and Typecasting

• Keccak256: a version of SHA256
  • Solidity 공식 문서에서 말하고 있는 abi.encodePacked()의 기능
  • abi: (contract)Application Binary Ineteface
  • abi.encodePacked(): non-standard, under 32byte는 not padding, array elements는 padded, still encoded in-place

Chapter 12: Putting it together

• '_'을 넣어서 선언한 함수는 calling 할 때도 '_' 붙일 것!
• 나는 붙일지 말지 헷갈렸다

Chapter 13: Events

• event는 emit으로 fire –> front-end에게 전달해야 한다.

Chapter 14: Web3.js

• We need to write a JavaScript frontend that interacts with the contract.