05 - Solidity Background and Context

دوره آموزشی کان آکادمی ۲۰۲۱ Chapter 3 - Smart Contracts
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Solidity Background and Context

solidity logo

Solidity is "an object-oriented, high-level language for implementing smart contracts…programs which govern the behaviour of accounts within the Ethereum state” (source). While a few smart contract programming languages have developed over the years, Solidity remains the most dominant one.

As we mentioned earlier, Solidity is a higher-order language meaning that the code deployed with a smart contract is not Solidity, but rather EVM bytecode. Solidity is an abstraction on top of that fundamental language so we don’t have to be writing code that looks like this:

PUSH1 0x80 PUSH1 0x40 MSTORE PUSH1 0xE PUSH1 0x0 SSTORE CALLVALUE DUP1
 ISZERO PUSH1 0x14 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH1 0x35
 DUP1 PUSH1 0x22 PUSH1 0x0 CODECOPY PUSH1 0x0 RETURN INVALID PUSH1 0x80 
PUSH1 0x40 MSTORE PUSH1 0x0 DUP1 REVERT INVALID LOG1 PUSH6 0x627A7A723058 KECCAK256 RETURNDATASIZE 0x25 0xb6 0xcf CALLDATALOAD LOG1 DUP16 PUSH9 
0x27AC943141CFD6D0FA MSTORE SHL DUP6 LOG4 PUSH8 0x7FADA153CC03D771
 BLOCKHASH 0xb3 STOP 0x29

But, rather code that looks like this:

pragma solidity >=0.4.0 <0.9.0; 
contract MyContract { 
   uint i = 10 + 2 * 2; 
}

While both these blocks of code describe the same operation, the second version (Solidity) is much easier to read and write.

General Characteristics of Solidity

Solidity uses the ECMAScript syntax like JavaScript, to make it approachable for web developers. However, do not be lulled into complacency! Solidity is much more demanding in its requirements.

Some of Solidity’s basic characteristics:

  • Case Sensitive
  • Statement termination via a semicolon ;
  • Files use the .sol extension
  • Statically typed Types need to be known at compile time. This makes Solidity more like TypeScript than JavaScript in practice.
  • Various compilation options Solidity compiling can be done on the command line by Solc, you can compile it in a web-browser using Remix, or compile it as part of a smart contract development framework like Truffle or Hardhat.
  • Compiles down to EVM bytecode Which then runs within the Ethereum Virtual Machine when deployed to a network

Overall, the Solidity workflow can be illustrated as follows:

graphic showing workflow of solidity to EVM

In this section, we’re going to go over the basic conventions of Solidity. We’re also going to start building smart contracts and discussing their general structure and design patterns.

We can’t emphasize this enough: smart contract coding is both really exciting and really dangerous! We see smart contracts rekt every day! We want to both give you all the tools to both build with creativity and confidence. Let’s go!

Additional Material

If you’d like some other places to learn Solidity, you can also check out these great resources. To be clear, we’ll definitely be teaching you Solidity along with how to develop dapps. We also want to provide any external help we can as well!