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Interact with any Core contract

About call and callView​

The magic contract provides you with a solidity interface to the core contracts. Some functions like getL2BalanceBaseTokens are wrapped in the magic contract directly, others you need to call yourself. You can do that with the call and callView functions.

WASM

You can also use call and callView to interact with WASM contracts.

Example Code​

  1. Get the AgentID from the sender by calling ISC.sandbox.getSenderAccount().
ISCAgentID memory agentID = ISC.sandbox.getSenderAccount();
  1. Initialize the parameters for the call by creating a new ISCDict. As you can see in the docs, getl2balancenativetokens takes two parameters.: the Agent ID and the native token ID. So, you have to create a dictionary with two key-value pairs. The key of the first pair (Agent ID) has to be a and the key for the second pair (native token ID) N.
ISCDict memory params = ISCDict(new ISCDictItem[](2));
params.items[0] = ISCDictItem("a", agentID.data);
params.items[1] = ISCDictItem("N", nativeTokenID);
  1. Now, you can use callView to call our contract. The first parameter is the core contract hname, which we can get with the helper utility hn, and the second parameter is the function we want to call. The last parameter is the dictionary with all function parameters.
ISCDict memory result = ISC.sandbox.callView(
    ISC.util.hn("accounts"),
    ISC.util.hn("balanceNativeToken"),
    params
);
  1. Next, you can either return or emit the result.
emit NativeTokenBalance(bytesToUint(result.items[0].value));
Return Dictionary

Keep in mind that the call and callView functions will always return a dictionary. The values of this dictionary are always of type byte, so you need to take care of converting it yourself.

Full Example Code​

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@iota/iscmagic/ISC.sol";

contract NativeTokenBalance {
    event NativeTokenBalance(uint balance);

    function getNativeTokenBalance(bytes memory nativeTokenID) public {
        ISCAgentID memory agentID = ISC.sandbox.getSenderAccount();

        ISCDict memory params = ISCDict(new ISCDictItem[](2));
        params.items[0] = ISCDictItem("a", agentID.data);
        params.items[1] = ISCDictItem("N", nativeTokenID);

        ISCDict memory result = ISC.sandbox.callView(
            ISC.util.hn("accounts"),
            ISC.util.hn("balanceNativeToken"),
            params
        );

        emit NativeTokenBalance(bytesToUint(result.items[0].value));
    }

    function bytesToUint(bytes memory b) internal pure virtual returns (uint256) {
        require(b.length <= 32, "Bytes length exceeds 32.");
        return abi.decode(abi.encodePacked(new bytes(32 - b.length), b), (uint256));
    }
}