Solidity简介 #

比特币脚本 (2009)
    ↓
以太坊白皮书 (2013) ← Vitalik Buterin
    ↓
Solidity开发 (2014) ← Gavin Wood
    ↓
以太坊主网启动 (2015)
    ↓
Solidity持续演进 (2015-至今)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract SimpleStorage {
    uint256 public storedData;

    function set(uint256 x) public {
        storedData = x;
    }

    function get() public view returns (uint256) {
        return storedData;
    }
}

uint256 balance = 100;
address owner = 0x1234...;
bool isActive = true;

// Solidity 0.8.x 内置溢出检查
uint256 a = type(uint256).max;
uint256 b = a + 1; // 自动revert，防止溢出

contract Immutable {
    uint256 public value;
    
    function setValue(uint256 _value) public {
        value = _value;
    }
}
// 合约部署后无法修改代码，只能通过状态变量更新数据

// 循环操作消耗大量Gas
function sum(uint256[] memory arr) public pure returns (uint256) {
    uint256 total = 0;
    for (uint256 i = 0; i < arr.length; i++) {
        total += arr[i];
    }
    return total;
}

// 状态变量存储在链上，成本高昂
contract Storage {
    string public largeData; // 存储大量数据成本很高
}

// 简化的借贷合约示例
contract SimpleLending {
    mapping(address => uint256) public deposits;
    
    function deposit() public payable {
        deposits[msg.sender] += msg.value;
    }
    
    function withdraw(uint256 amount) public {
        require(deposits[msg.sender] >= amount, "Insufficient balance");
        deposits[msg.sender] -= amount;
        payable(msg.sender).transfer(amount);
    }
}

// 简化的NFT合约
contract SimpleNFT {
    mapping(uint256 => address) public ownerOf;
    mapping(address => uint256) public balanceOf;
    
    function mint(uint256 tokenId) public {
        require(ownerOf[tokenId] == address(0), "Already minted");
        ownerOf[tokenId] = msg.sender;
        balanceOf[msg.sender]++;
    }
}

// 简化的投票合约
contract SimpleDAO {
    struct Proposal {
        string description;
        uint256 votes;
        bool executed;
    }
    
    Proposal[] public proposals;
    
    function createProposal(string memory description) public {
        proposals.push(Proposal(description, 0, false));
    }
    
    function vote(uint256 proposalId) public {
        proposals[proposalId].votes++;
    }
}

// 简化的游戏道具合约
contract GameItem {
    struct Item {
        string name;
        uint256 power;
        address owner;
    }
    
    mapping(uint256 => Item) public items;
    
    function createItem(string memory name, uint256 power) public {
        items[block.timestamp] = Item(name, power, msg.sender);
    }
}

区块链开发技能树
├── 智能合约开发
│   ├── Solidity ← 核心语言
│   ├── Vyper
│   └── Yul
├── 前端开发
│   ├── Web3.js
│   └── Ethers.js
└── 后端开发
    ├── Node.js
    └── The Graph