With the growth of Web3, come more choices for Web3-related programming languages. These languages are primarily used for writing automatically executing smart contracts that form the foundation of blockchain platforms and Web3 applications. Each such language may have different characteristics and benefits.
One such programming language developed specifically for smart contracts on Ethereum is Solidity. It is a high-level object-oriented programming language for implementing smart contracts on Ethereum and other compatible blockchains.Â
In this article, we will talk about Solidity, what it is used for, and what languages Solidity is based on.
Evolution of Solidity
The idea for Solidity programming was proposed in 2014 by Gavin Wood. It was later developed by the team comprising Christian Reitwiessner, Alexberegszaszi, and other former Ethereum core contributors. A dominant language on the Ethereum blockchain, Solidity is licensed under GNU General Public License v3.0.
Since 2015, it has grown by leaps and bounds and enables smart contract programming on not just Ethereum but also on other platforms like Monax. Even the Society for Worldwide Interbank Financial Telecommunication(SWIFT) has developed a proof of concept with Solidity that runs on Monax’s Burrow blockchain.
Key Concepts of Solidity
To understand Solidity better, it is crucial to first understand certain concepts associated with the Ethereum blockchain.
Smart Contracts
These are high-level programming scripts that are automatically executed when certain predetermined conditions of the agreement are met. Smart contracts are first compiled on the Ethereum Virtual Machine(EVM) byte code and are then deployed on the blockchain for further execution.
They make it possible to execute contracts and perform transactions without the involvement of any third parties. Smart contracts are irreversible and also offer the advantage of easy tracking of transactions.
Ethereum Virtual Machine(EVM)
It is an integral part of the Ethereum network as it provides the runtime environment for executing smart contracts. EVM is Turing-complete and can, hence, run any program coded in any language.
It, therefore, helps developers in creating a variety of smart contracts and DApps on the Ethereum blockchain. In other words, EVM is the overarching program under which several smaller programs are executed.
EVM also leverages a global network of public nodes to ensure security. It is key to preventing Denial-of-Service(DoS) attacks and confirming that programs are not able to access each other’s state.
What is Solidity used for?
Development of DApps
Solidity is an object-oriented programming language that is used for implementing smart contracts on Ethereum. It is easy to understand and has flexible functionality which makes it a great option for a blockchain coding language.
Solidity can be used to write secure Ethereum-compatible smart codes for any EVM-compatible blockchain. This broad compatibility is the reason developers prefer Solidity to develop their DApps.
Crowdfunding
Traditional crowdfunding mechanisms suffer from various issues such as data management problems and third-party commission issues. Smart contracts created with Solidity can be used to address these issues and streamline the crowdfunding process. They can help in removing the role of third parties and make the whole process more transparent.
Voting
Booth capturing, fraudulent voting, data manipulation, and voting machine manipulation are some problems that plague the election process. Such practices erode the integrity of the voting process and weaken democracy.
Here, smart contracts can be an effective mechanism to address such dishonest tactics. Solidity can be used to create a voting mechanism that is automated, transparent, and runs without any major downtime.
Blind Auctions
Implementing a blind auction mechanism is much more feasible on Ethereum using Solidity than anywhere else. An open auction where everyone can easily view each other’s bids can be constructed with Solidity. This can be followed by a blind auction where no one can view the bids until the auction is over.
What Language Is Solidity Based On?
Solidity is heavily influenced by various programming languages such as C++, Python, and JavaScript.
C++
Solidity’s syntax for variable declarations and loops is nearly identical to C++. Additionally, it also supports C++ style function overloading that is needed when two functions have the same name but accept different parameters.
Both implicit and explicit type conversions are possible on Solidity. Thus, variable types can either be cast with explicit developer code or are automatically converted as required by a computation.
Python
Solidity is similar to Python in the sense that it uses C3 linearization, and multiple inheritance and maintains the super keyword. The Python-based programming language Vyper is similar to Solidity and is designed to improve the security of smart contracts on EVM-compatible blockchains.
JavaScript
Solidity uses the function keyword for defining functions just like JavaScript. JavaScript enthusiasts would be, therefore, at home with the former. Further, as Solidity is statically typed, developers can use libraries as well as create complex types on it.
Data Types in Solidity
Although Solidity divides data into many types like other programming languages, it is unique in the sense that it has several simple kinds that can be merged to form more complex types.
Here, it is important to specify the type of each variable as Solidity is a statically typed language. The compiler can then verify the application of the variables with data types.
Solidity has both value-type variables and reference-type variables. The important ones here are the value types which are the fundamental data types offered by Solidity. They are always passed by value and a copy is made whenever the variables are used as function parameters.
There are mainly six value types in Solidity which are:
Integers
These data types store whole numbers and are either signed or unsigned. Here, signed integers store both positive and negative values while unsigned integers only store non-negative values. Signed integers are denoted by int while uint is used to denote unsigned ones.
Booleans
This data type can hold only two constant values i.e. true or false. The bool keyword is used to declare booleans data type.
Fixed Point Numbers
They represent decimal numbers in Solidity but are not yet fully supported by the EVM. Signed and unsigned fixed point numbers of different sizes can be declared as fixed or unfixed.
Addresses
This data type is used to store Ethereum wallet or smart contract addresses. These are typically around 20 bytes and are generally suffixed with the keyword ‘payable.’ This restricts the address type to only store wallet addresses and uses the send crypto functions.
Bytes and Strings
Bytes store a fixed-size character set while a character set larger than or equal to a byte is stored in a string. The length of a byte can be up to 32 but the string has a dynamic length. As a byte uses less gas, it is always better to utilize it rather than a string when we know the length of the data.
Enums
Enums are user-defined data types. They are used to give names to integral constants in smart contracts. This makes the contracts easy to read and manage and less prone to mistakes. Unsigned integer values starting from zero can be used to represent enum options.
Advantages of Solidity
Support for Complicated Data Types
Alongside fundamental data types, Solidity also supports complex data types and member variables. All these data types have a specific role and help in creating secure smart contracts on Ethereum.
Easy to Learn
Solidity is an easy-to-learn language for developers familiar with C++ or Python. The resemblance to these languages makes it easy for developers to familiarize themselves with the concepts and syntax of Solidity.
Application Binary Interface(ABI)
ABI, which facilitates communication between different smart contracts, is the default method for interaction between contracts on Ethereum. Further, an error is issued by ABI if the compiler detects any data type mismatch. Thus, it helps in preventing syntax errors.
Natural Language Specification
Solidity uses Natural Language Specification to turn user-centric specifications into a language that machines can easily comprehend.
Comprehensive Documentation
There are a plethora of open-source documents regarding Ethereum and EVM use cases. Developers can, thus, consult these resources to make the task of constructing complex applications on the Ethereum network a little easier.
What Blockchains Use Solidity?
Solidity’s popularity stems from the fact that it can be used on not just Ethereum but other EVM-compatible blockchains as well. Some such blockchains are:
Polkadot
Polkadot is a project whose aim is to integrate multiple blockchains into a single one using a relay chain. In other words, it is a blockchain that supports other blockchains. The relay chain is the main network while the user-created ones are called parachains. Polkadot’s goal is to make parachains interoperable such that there is more room for scalability and increased bandwidth.
BNB Chain
The Binance Smart Chain(BSC) was merged with the Binance Chain in 2022 to form the BNB Chain. Created by the cryptocurrency exchange Binance, it is an EVM-compatible blockchain that uses Solidity for its smart contracts. BNB Chain has a native BNB token which serves as its ‘gas’ token.
Avalanche
Avalanche is an EVM-compatible blockchain platform that is also a rival of Ethereum. It uses Solidity for its smart contracts to get better blockchain interoperability. Avalanche is a multi-chain platform and has three blockchains: The X-Chain where assets are created and traded, the C-Chain where smart contracts are executed and the P-Chain which coordinates network validators.
Conclusion
Solidity occupies an important place in the blockchain programming landscape. This object-oriented language is what powers Ethereum’s smart contracts and makes the development of DApps possible on the blockchain.
It is a powerful and flexible language which is why developers prefer Solidity to other programming languages for developing applications on Ethereum and other EVM-compatible blockchains. There are several resources available with which you can start learning the ropes of Solidity.