In my previous post, I described the extensions of the most used token standard — ERC20. Now it’s time for the second most popular token standard — ERC721. All extensions come from the OpenZeppelin library. The main and also the only obligatory interface is ERC721, which is the simplest implementation of ERC721 standard. Except this, … Read more
The ERC20 standard is one of the most known standard in the Ethereum ecosystem. It provides basic functionality to create and transfer the fungible tokens. But here I don’t want to focus on the details of ERC20 standard and a way how to implement it, because on the Internet there is a plenty of that … Read more
In my previous post, I wrote about two mainly used proxy pattern: Transparent Proxy Pattern and UUPS (Universal Upgradeable Proxy Standard). As I said there, this pattern was created to avoid proxy selector clashing. The Diamonds, also known as Multi-Facet Proxy, solves this problem too. But except that, it solves one more problem. New problem … Read more
Delegatecall is a very specific function which used rashly could be very dangerous. But used after reflection gives a plenty of facilities and possibilities. What does this function make? When a contract makes a function call using delegatecall it loads the function code from another contract and executes it as if it were its own … Read more
If we want to save something inside our contract, but we don’t want others could read it, we will use just private state (more about state here), won’t we? It’s not so simple. Every information saved in blockchain is public, even if it is private variable. So why do we use private variable, and what … Read more
Imagine a world where everyone knows only two letters, no less, no more. Everyone words which they use is created from this to letters. Additionally, let’s assume these letters are also numbers and in this world there aren’t more number than these two. Is it sound ridiculous? But what if I say to you, that … Read more
The idea of smart contract is great. By them, Ethereum is more flexible than for example Bitcoin. We can write abstract programs which are able to more than just track Ether — DAO, NFT, DApps and so more. Without smart contracts, create that kind of thing would be impossible. But let’s focus on them by … Read more
Constructor is a special function declared using constructor keyword. It’s not an obligatory function which is called just one, and never again. The moment of call is when our smart contract is created. Constructor gives us a possibility to initialize state variable then. After a constructor code executed, the final code is deployed to blockchain. … Read more