How can you write smart contracts in Rust with Substrate?

Learned Substrate years ago while working on Polkadot ecosystem projects. Substrate is a comprehensive framework that allows developers to create their own blockchain using a wide range of modular components.

Substrate, an open-source framework, simplifies creating custom blockchain platforms. It offers modular components like consensus, networking, storage, and runtime for customization. Substrate also enables interoperability with other blockchains via the Polkadot network, supporting cross-chain communication and collaboration.

To write smart contracts in Rust with Substrate, use the ink! smart contract library. It allows you to define smart contract logic using Rust syntax and integrates seamlessly with Substrate's blockchain framework. The ink! library provides a set of macros and utilities for writing and deploying smart contracts on Substrate.

Much of what makes Substrate a flexible and extensible framework for creating mission-critical software is owed to Rust. Being the language of choice for Substrate, Rust is a highly performant programming language and a first choice for the following reasons: Rust is fast: it's statically typed at compile time, making it possible for the compiler to optimize the code for speed and for developers to optimize for a specific compilation target. Rust is portable: it's designed to run on embedded devices with support for any type of operating system. Rust is memory safe: it has no garbage collector and it checks each and every variable you use and every memory address you reference to avoid any memory leaks. Rust is Wasm first

Well...Rust is like the superhero of programming ??♂?it's modern, speedy, and safety-conscious. Forget about those pesky errors like memory leaks or null pointers;:::::: Rust's got strict rules at compile time to keep things in check. It's not just about safety though; Rust flaunts cool features like generics, traits, macros, and pattern matching that make coding a breeze.

Rust prioritizes memory safety and crash prevention, keeping your chain secure from common programming bugs like memory leaks and data races. Rust manages the parallel processing seamlessly with built-in features, ensuring smooth and efficient transaction handling.

Writing smart contracts in Rust with Substrate is streamlined using the ink! library, a Rust-based domain-specific language. ink! enables developers to write contracts as Rust structs with clear annotations for constructors and public methods, simplifying development. It automates low-level blockchain tasks like encoding and storage management, allowing focus on business logic. Key in ecosystems like Polkadot and Kusama, ink! combines Rust's efficiency with ease of smart contract creation, enhancing developer experience in blockchain development.

ink! is an embedded domain-specific language for the popular Rust programming language. This means that you can use all the normal Rust syntax plus some specifics that we added to make the language suitable for the smart contract world. The pallet-contracts takes these ink! contracts and executes them safely. So in short: with ink! you can write smart contracts in Rust for blockchains built with Substrate that include pallet-contracts.

Smart contract deployment on Substrate is a little different than on traditional smart contract blockchains. In Substrate, the contract deployment process is split into two steps: 1. Putting your contract code on the blockchain 2. Creating an instance of your contract With this pattern, contract code like the ERC20 standard can be put on the blockchain one single time, but instantiated any number of times. No need to continually upload the same source code over and waste space on the blockchain.

which are portable and efficient. cargo-contract can also generate metadata for your smart contracts, which are JSON files that describe the interface and the types of your contract.

The best way to interact with blockchain is via RPC APIs. Substrate-subxt, the most popular client libaries, built to interface with the substrate chain. It provides light client support, making it possible to work with untrusted substrate nodes. It provides light client support, making it possible to work with Substrate-based chains without having to run a full node. It is written in Rust and uses the Substrate API to communicate with the node.

The Substrate RPC API is a set of methods that allow you to query and manipulate the state of the blockchain and the smart contracts. One of the most popular client libraries for Substrate is substrate-subxt, which is written in Rust and provides a type-safe and async-friendly interface.

Rust is fast. It’s statically typed at compile time, meaning the compiler can optimize the code for speed, and developers can optimize for a specific compilation target. Rust is portable. It’s designed to run on a myriad of devices, including embedded ones, and supports any operating system. Rust is memory safe. With no garbage collector, it diligently checks every variable you use and every memory address you reference to avoid any memory leaks. Rust is WebAssembly, or Wasm, first. It offers robust support for compiling to Wasm, which is a key feature in the blockchain space.

Well....To write smart contracts in Rust with Substrate, you'll want to leverage the Substrate FRAME framework.... ?? FRAME provides a set of modules and tools for building custom blockchains and smart contracts. Start by setting up your Substrate project, define your custom runtime logic in Rust, and use FRAME's modules for functionalities like governance or tokens. ???

Substrate-subxt provides a seamless interface for interacting with the blockchain, ensuring that agency developers can efficiently manage and maintain smart contracts post-deployment.