March 2022
Intermediate to advanced
293 pages
5h 31m
Chinese
Content preview from 精通区块链
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100 ｜ 第 4 章
gas
解决了在区块链中操作编程语言的危险之一。开发者可以在以太坊上运行
DApp
，而不会遇到所谓的停机问题（
halting problem
），或无法防止代码无
法终止或无限循环（
infinite loop
）。以太坊要求将
gas
用于计算智能合约中
执行的代码，以便使得
DApp
尽可能高效。对于每一笔以太坊交易，开发者
都会指定一个燃料限制（
gas limit
），所以如果出现无限循环，交易最终会耗
尽
gas
，而矿工依然会赚取运行交易的费用。
4.2.2
案例：
ICO
有许多使用智能合约实计算机化的交易协议的应用程序。
Ian Grigg
在
1996
年
提出的李嘉图合约（
Ricardian Contracts
）的概念让我们深入了解了该技术的
应用领域。创新之处包括使用加密哈希函数进行识别，并将法律元素通过加
密哈希定义为计算机可读的内容。通过执行一系列指令（通过智能合约）并
将其与账户系统（通过区块链）关联起来，以太坊平台可用被用来运行许多
不同的应用程序。
在以太坊发布后的最初几年，开发者生态系统的成长需要时间。但开发者意
识到，以太坊最强大的功能是可以利用智能合约以自动化且安全的方式筹集
加密货币资金，即之前提及过的
ICO
。例如，一个需要筹集资金来启动一个
概念的项目可以建立一个智能合约来接受以太币。作为回报，可以给与捐赠
者建立在以太坊之上的可赎回的加密货币。
ICO
的合法性是值得商榷的，许多项目因其引起的法律问题而提前终止。这
个问题在第
9
章有更详细的讨论。
筹集加密货币资金来启动项目的想法并不是从以太坊才有的。 ...
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