Solidity Cheatsheet

A quick Solidity → Sway cross reference for the most commonly used items

  • block.timestamp
  • msg.sender
  • etc

If something is missing here you can most likely find it in the Sway STD Library

In Sway, you can use various methods to get blockchain state information and perform complex mathematical operations.

  1. Retrieving Block Information:
    • Sway provides functions such as height() and timestamp(), which allow smart contracts to retrieve the current block's height and timestamp.
    • In the get_blocknumber and get_blocktime functions, we demonstrate how to use these functions to get the number and timestamp of the current block.
  2. U128 Integer Type:
    • Sway does not have a built-in uint128 type, but it can be represented using the U128 structure, which consists of two u64 type values.
    • In the get_u128_number function, we demonstrate how to use the U128 structure to perform addition operations and treat it as a uint128 type value.
    • It's worth noting that the Sway library also provides a complete list of U128 operations, including exponents, addition, subtraction, multiplication, division, square roots, etc. These operations can be found in the Sway U128 documentation.

In the provided code, we define a smart contract named SolidityCheatsheet with four functions: get_blocknumber, get_blocktime, get_msg_sender, and get_u128_number.

  • The get_blocknumber function returns the number of the current block.
  • The get_blocktime function returns the timestamp of the current block.
  • The get_msg_sender function returns the sender of the current message.
  • The get_u128_number function returns the sum of two U128 type values, which is equivalent to a uint128 type value.

This simple example is intended to show you how to get blockchain state information and perform U128 integer type operations in Sway. We hope this tutorial helps you better understand these features in Sway.

All Examples
// The underlying smart contracts written in Sway are no different than those in Solidity
// Some bytecode is deployed with an API and state to interact with
contract;

// The ABI (Application Binary Interface) clearly defines the signature of the functions present in the contract
abi HelloModular {
    // The "annotation" storage indicates the impure actions of the function
    // In this case the greet() function only has reading capabilities.
    // Note: Storage can only be found in contract type programs
    #[storage(read)]
    fn my_lucky_number() -> u64;
}

// Storage contains all of the state available in the contract 
storage {
    lucky_number: u64 = 777,
}

// The actual implementation of ABI for the contract
impl HelloModular for Contract {
    #[storage(read)]
    fn my_lucky_number() -> u64 {
        storage.lucky_number.read()
    }
}