This library provides a simple API for interacting with an embedded Ethereum Virtual Machine (EVM).

[dependencies]
simular-core = "0.2.5"

Supports

• Both an in-memory database and the ability to fork state from a remote node
• Snapshot of EVM state for later use
• Both raw encoding/decoding of function calls as well as alloy SolTypes
• Lightweight creation of ABI from human-readable syntax

Examples

Create and interact with the EVM

use simular_core::{BaseEvm, generate_random_addresses};use alloy_primitives::{Address,U256};// Generate some random addresseslet addresses = generate_random_addresses(2);let bob = addresses[0];let alice = addresses[1];// create the EVM with in-memory database (default)letmut evm = BaseEvm::default();// create 2 accounts. Bob w/ 2 ether, alice w/ none
evm.create_account(bob,Some(U256::from(2e18))).unwrap();
evm.create_account(alice,None).unwrap();// check the balancesassert!(evm.get_balance(bob).unwrap() == U256::from(2e18));assert!(evm.get_balance(alice).unwrap() == U256::from(0));

Fork a remote contract

Interacting with a remote contract pulls the state of the remote contract into the local in-memory database for use.

use simular_core::{BaseEvm, generate_random_addresses,ContractAbi};use alloy_primitives::{Address,U256, address};// create ABI inlinelet abi = ContractAbi::from_human_readable(vec!["function totalSupply() (uint256)"]);// create a fork using the latest blocklet fork_info = CreateFork.latest_block(URLOFJSON-RPCNODE);letmut evm = BaseEvm::new(Some(fork_info));// remote contract address.// using DAI: 0x6B175474E89094C44Da98b954EedeAC495271d0Flet contract_address = address!("6B175474E89094C44Da98b954EedeAC495271d0F");// encode the function calllet(encoded_total_supply, _, decoder) =
abi.encode_function("totalSupply","()").unwrap();// call the function on the remote contractlet output = evm.transact_call(
contract_address,
encoded_total_supply,U256::from(0)).unwrap();// decode the resultlet value = decoder.unwrap().abi_decode(&output.result)println!("total supply: {:?}", value);

See uniswap for an example of using a fork and snapshot to trade a pair on Uniswap.

To run the example:

> cargo run --example uniswap

Standing on the shoulders of giants...

Thanks to the following projects for making this work possible!

• revm
• alloy-rs
• foundry-rs for much of the design influence