Solidity入门1

Solidity 是一门面向合约的、为实现智能合约而创建的高级编程语言,为了体验Solidity语言在智能合约应用场景广泛性,跟着Solidity官方文档和中文社区学习做两个简单例子以熟悉安装、配置、使用集成开发环境和基础智能合约实际应用。
标准以太坊货币例子合约熟悉开发环境 任何语言都一样,让我们来快速体验一下Solidity的helloworld吧,把前几天学到的货币合同copy来直接上环境一睹为快:

  1. 访问https://remix.ethereum.org/网站,初始加载比较慢,可以随便点点最左边的图标看看有些什么功能;
  2. 点File explorers在default_workspace边上,点Create创建一个新空间workspace_mark;点Create New File在contracts下创建一个合约;
Solidity入门1
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  1. 将如下代码保存在合约中;
pragma solidity ^0.4.16; interface tokenRecipient { functionreceiveApproval(address _from, uint256 _value, address _token, bytes _extraData)external; }contract t_first_Token { string public name; string public symbol; uint8 public decimals = 18; // 18 是建议的默认值 uint256 public totalSupply; mapping (address => uint256) public balanceOf; // mapping (address => mapping (address => uint256)) public allowance; event Transfer(address indexed from, address indexed to, uint256 value); event Burn(address indexed from, uint256 value); function t_first_Token(uint256 initialSupply, string tokenName, string tokenSymbol) public { totalSupply = initialSupply * 10 ** uint256(decimals); balanceOf[msg.sender] = totalSupply; name = tokenName; symbol = tokenSymbol; }function _transfer(address _from, address _to, uint _value) internal { require(_to != 0x0); require(balanceOf[_from] >= _value); require(balanceOf[_to] + _value > balanceOf[_to]); uint previousBalances = balanceOf[_from] + balanceOf[_to]; balanceOf[_from] -= _value; balanceOf[_to] += _value; Transfer(_from, _to, _value); assert(balanceOf[_from] + balanceOf[_to] == previousBalances); }function transfer(address _to, uint256 _value) public returns (bool) { _transfer(msg.sender, _to, _value); return true; }function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) { require(_value <= allowance[_from][msg.sender]); // Check allowance allowance[_from][msg.sender] -= _value; _transfer(_from, _to, _value); return true; }function approve(address _spender, uint256 _value) public returns (bool success) { allowance[msg.sender][_spender] = _value; return true; }function approveAndCall(address _spender, uint256 _value, bytes _extraData) public returns (bool success) { tokenRecipient spender = tokenRecipient(_spender); if (approve(_spender, _value)) { spender.receiveApproval(msg.sender, _value, this, _extraData); return true; } }function burn(uint256 _value) public returns (bool success) { require(balanceOf[msg.sender] >= _value); balanceOf[msg.sender] -= _value; totalSupply -= _value; Burn(msg.sender, _value); return true; }function burnFrom(address _from, uint256 _value) public returns (bool success) { require(balanceOf[_from] >= _value); require(_value <= allowance[_from][msg.sender]); balanceOf[_from] -= _value; allowance[_from][msg.sender] -= _value; totalSupply -= _value; Burn(_from, _value); return true; } }

  1. 选择Solidity Compiler出新界面后,点击Compile t_first_token.sol编译智能合同,点击Publish on Swarm将智能合同发表;
  2. Deploy按下图三步发布合同到JavaScript vm中;
    发布初始构造需要货币总量、币名和币编号。
Solidity入门1
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Solidity入门1
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Solidity入门1
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  1. 操作JavaScript vm中合同的函数并查询变量;
    使用MetaMask钱包等的地址0x7a7644C0F817eb94C823781E20B2F2EcE2916967调用(JavaScript vm要进行格式验证)。
Solidity入门1
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Solidity入门1
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Solidity入门1
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  1. 这样Solidity编辑的智能合同,一个仿以太币就show出来了。
合同间调用例子看智能合约的变化
  1. 学习生产环境的配置看考Hardhat + VS code(https://www.yuque.com/bernieg...)文档
    安装运行hardhat:
    npm install --save-dev @nomiclabs/hardhat-waffle ethereum-waffle chai @nomiclabs/hardhat-ethers ethers
    npx hardhat
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由上到下运行如下命令:
npx hardhat accounts
npx hardhat compile
npx hardhat test
npx hardhat node
node scripts/sample-script.js
npx hardhat help
npx hardhat test可以得到真正的helloworld合同输出
Deploying a Greeter with greeting: Hello, world!
Changing greeting from 'Hello, world!' to 'Hola, mundo!'
npx hardhat node
Started HTTP and WebSocket JSON-RPC server at http://127.0.0.1:8545/
  1. 将上面t_first_token.sol合同转移到hardhat环境中运行
    合同升级到0.7+,修改相应代码如下( //修改版本升级)
    -wanning:加license标签,constrctor 去掉public修饰
    -error:版本,加memory修饰,比较adress,this 被adress强制转换等
//SPDX-License-Identifier: Unlicense //修改版本升级 pragma solidity >=0.7.0; //修改版本升级interface tokenRecipient { functionreceiveApproval(address _from, uint256 _value, address _token, bytes memory _extraData)external; //修改版本升级}contract t_first_token { string public name; string public symbol; uint8 public decimals = 18; // 18 是建议的默认值 uint256 public totalSupply; mapping (address => uint256) public balanceOf; // mapping (address => mapping (address => uint256)) public allowance; event Transfer(address indexed from, address indexed to, uint256 value); event Burn(address indexed from, uint256 value); //function t_first_token(uint256 initialSupply, string memory tokenName, string memory tokenSymbol) public { constructor(uint256 initialSupply, string memory tokenName, string memory tokenSymbol){//修改版本升级 totalSupply = initialSupply * 10 ** uint256(decimals); balanceOf[msg.sender] = totalSupply; name = tokenName; symbol = tokenSymbol; }function _transfer(address _from, address _to, uint _value) internal { require(_to != 0x0000000000000000000000000000000000000000); //修改版本升级 require(balanceOf[_from] >= _value); require(balanceOf[_to] + _value > balanceOf[_to]); uint previousBalances = balanceOf[_from] + balanceOf[_to]; balanceOf[_from] -= _value; balanceOf[_to] += _value; emit Transfer(_from, _to, _value); assert(balanceOf[_from] + balanceOf[_to] == previousBalances); }function transfer(address _to, uint256 _value) public returns (bool) { _transfer(msg.sender, _to, _value); return true; }function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) { require(_value <= allowance[_from][msg.sender]); // Check allowance allowance[_from][msg.sender] -= _value; _transfer(_from, _to, _value); return true; }function approve(address _spender, uint256 _value) public returns (bool success) { allowance[msg.sender][_spender] = _value; return true; }function approveAndCall(address _spender, uint256 _value, bytes memory _extraData) public returns (bool success) {//修改版本升级 tokenRecipient spender = tokenRecipient(_spender); if (approve(_spender, _value)) { spender.receiveApproval(msg.sender, _value, address(this), _extraData); //修改版本升级 return true; } }function burn(uint256 _value) public returns (bool success) { require(balanceOf[msg.sender] >= _value); balanceOf[msg.sender] -= _value; totalSupply -= _value; emit Burn(msg.sender, _value); return true; }function burnFrom(address _from, uint256 _value) public returns (bool success) { require(balanceOf[_from] >= _value); require(_value <= allowance[_from][msg.sender]); balanceOf[_from] -= _value; allowance[_from][msg.sender] -= _value; totalSupply -= _value; emit Burn(_from, _value); return true; } }

3.添加计数合同,更新t_first_token.sol添加变量
test测试合同中的函数调用
const { expect } = require("chai"); describe("Greeter", function() { it("Should return the new greeting once it's changed", async function() { const Greeter = await ethers.getContractFactory("Greeter"); const greeter = await Greeter.deploy("Hello, world!"); await greeter.deployed(); expect(await greeter.greet()).to.equal("Hello, world!"); const setGreetingTx = await greeter.setGreeting("Hola, mundo!"); // wait until the transaction is mined await setGreetingTx.wait(); expect(await greeter.greet()).to.equal("Hola, mundo!"); }); }); describe("t_first_token", function() { it("Should return mane", async function() { const _t_first_token = await ethers.getContractFactory("t_first_token"); const t_first_token = await _t_first_token.deploy(2000,"markcion","18188"); await t_first_token.deployed(); expect(t_first_token.burn(111)); }); }); describe("t_first_token/Greeter", function() { it("Should return t_first_token/Greeter", async function() { const _t_first_token = await ethers.getContractFactory("t_first_token"); const t_first_token = await _t_first_token.deploy(2000,"markcion","18188"); await t_first_token.deployed(); const Greeter = await ethers.getContractFactory("Greeter"); const greeter = await Greeter.deploy("Hello, world!"); await greeter.deployed(); expect(t_first_token.inc()); expect(greeter.inc()); expect(greeter.inc()); }); });

npx hardhat test
Greeter
Deploying a Greeter with greeting: Hello, world!
Changing greeting from 'Hello, world!' to 'Hola, mundo!'
? Should return the new greeting once it's changed (1098ms)
t_first_token
Deploying a tokenName: markcion
? Should return mane (122ms)
t_first_token/Greeter
burn-totalSupply: 1999999999999999999889
Deploying a tokenName: markcion
t_first_token m: 2
Deploying a Greeter with greeting: Hello, world!
? Should return t_first_token/Greeter (173ms)
3 passing (1s)
Greeter m: 2
Greeter m: 3
  1. 调用关系并简单分析
    在Solidity中,如果只是为了代码复用,我们会把公共代码抽出来,部署到一个library中,后面就可以像调用C库、Java库一样使用了。但是library中不允许定义任何storage类型的变量,这就意味着library不能修改合约的状态。如果需要修改合约状态,我们需要部署一个新的合约,这就涉及到合约调用合约的情况。
    合约调用合约有下面4种方式:
    1) CALL
    2) CALLCODE
    3) DELEGATECALL
    4) STATICCALL
【Solidity入门1】CALL vs. CALLCODE
CALL和CALLCODE的区别在于:代码执行的上下文环境不同。
具体来说,CALL修改的是被调用者的storage,而CALLCODE修改的是调用者的storage。
Solidity入门1
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CALLCODE vs. DELEGATECALL
实际上,可以认为DELEGATECALL是CALLCODE的一个bugfix版本,官方已经不建议使用CALLCODE了。
CALLCODE和DELEGATECALL的区别在于:msg.sender不同。
具体来说,DELEGATECALL会一直使用原始调用者的地址,而CALLCODE不会。
Solidity入门1
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将钱包和合约打通(高阶 持续更新)
Solidity语言特点及学习差异列表 (持续更新)
  1. solidity语法注意事项
    1)所有的标识符(合约名称,函数名称和变量名称)都只能使用ASCII字符集。UTF-8编码的数据可以用字符串变量的形式存储。(小心使用Unicode文本,因为有些字符虽然长得相像(甚至一样),但其字符码是不同的,其编码后的字符数组也会不一样。)
    2)变量
    uint (256位无符号整数),块的概念无处不在。
    address 类型是一个160位的值,且不允许任何算数操作。这种类型适合存储合约地址或外部人员的密钥对。
    mapping (address => uint) 黑匣子哈希表(无key集合访问)。
    3)合约版本变化,语法变化很大,使用编译版本限制。
    4)“undefined”或“null”值的概念在Solidity中不存在,但是变量声明后将有默认初始值,其初始值字节表示全部为零。任何类型变量的“默认值”是其对应类型的典型“零状态”。例如, bool 类型的默认值是 false 。 uint 或 int 类型的默认值是 0 。对于静态大小的数组和 bytes1 到 bytes32 ,每个单独的元素将被初始化为与其类型相对应的默认值。 最后,对于动态大小的数组 bytes 和 string 类型,其默认缺省值是一个空数组或空字符串。
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Solidity入门1
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