Lesson 2 - Building HelloWorld.sol in Remix

Coding HelloWorld.sol

• Solidity philosophy
• OOP basics of Solidity
• Contract Structure
  • SPDX License Identifier
  • Pragmas
  • Imports
  • Comments
  • Contract definition
• Variables
• Storage areas
  • Account storage
  • Memory
  • Stack
• Constructor function
• Functions
• Visibility
• Typing
• Return values

Detailed contract structure

• (Review) Contract structure
• (Review) Variables
• (Review) Storage
• What are interfaces
• What are contracts, indeed
• Multiple objects per file

References

https://docs.soliditylang.org/en/latest/grammar.html

https://docs.soliditylang.org/en/latest/structure-of-a-contract.html

Code Reference

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;

interface HelloWorldInterface {
    function helloWorld() external view returns (string memory);
    function setText(string memory newText) external;
}

contract HelloWorld is HelloWorldInterface {
    string private text;

    constructor() {
        text = "Hello World";
    }

    function helloWorld() public view override returns (string memory)  {
        return text;
    }

    function setText(string memory newText) public override {
        text = newText;
    }
}

Contract interaction

Part 1

• Contract interactions using Remix
• Viewing state changes through functions

Part 2

• State changing calls

Part 3

• Payable functions
• Experimenting with payable calls

Clean code and documentation

• (Review) Readability and standardization
• The Style guide
• Using the Linter
• Function order
• Layout
• Naming conventions
• Documentation
• NatSpec Format

References

https://docs.soliditylang.org/en/latest/natspec-format.html#natspec

Homework

• Create Github Issues with your questions about this lesson
• Read the references