This guide explains how to use the SDK to execute a contract call where one contract interacts with another contract. We will use a simple scenario involving a SimpleToken contract and a TokenDepositor contract.
SimpleToken and TokenDepositor Contracts In this example, we have a SimpleToken contract representing a basic token contract capable of holding balances for different addresses. We also have a TokenDepositor contract that deposits tokens into the SimpleToken contract.
SimpleToken Here's a simple token contract that allows holding balances:
contract;
use ::simple_token_abi::SimpleToken;
storage {
balances: StorageMap<b256, u64> = StorageMap {},
}
impl SimpleToken for Contract {
#[storage(read, write)]
fn deposit(address: b256, amount: u64) {
let current_balance = storage.balances.get(address).unwrap_or(0);
storage.balances.insert(address, current_balance + amount);
}
#[storage(read)]
fn get_balance(address: b256) -> u64 {
let balance = storage.balances.get(address).unwrap_or(0);
balance
}
}TokenDepositor The TokenDepositor contract imports the SimpleToken contract and calls its deposit function to deposit tokens:
contract;
use std::auth::msg_sender;
use ::simple_token_abi::SimpleToken;
abi TokenDepositor {
fn deposit_to_simple_token(contract_id: b256, amount: u64);
}
impl TokenDepositor for Contract {
fn deposit_to_simple_token(contract_id: b256, amount: u64) {
let simple_token_contract = abi(SimpleToken, contract_id);
let sender = msg_sender().unwrap();
let address: b256 = match sender {
Identity::Address(sender_param) => sender_param.into(),
_ => revert(0),
};
simple_token_contract.deposit(address, amount);
}
} Once both contracts are deployed, we can use the SDK to make the TokenDepositor contract to call the SimpleToken contract.
const amountToDeposit = 70;
const { value: initialBalance } = await simpleToken.functions
.get_balance(wallet.address.toB256())
.call();
expect(new BN(initialBalance).toNumber()).toBe(0);
await tokenDepositor.functions
.deposit_to_simple_token(simpleToken.id.toB256(), amountToDeposit)
.addContracts([simpleToken])
.call();
const { value: finalBalance } = await simpleToken.functions
.get_balance(wallet.address.toB256())
.call();
expect(new BN(finalBalance).toNumber()).toBe(amountToDeposit); Pay attention to the method addContracts called by the TokenDepositor contract. This method accepts an array of instances of deployed contracts. Without calling this method, the inter-contract call will not work.