Struct Encoding

Structs are user defined types that can group several variables:

struct MyStruct {
    address addr;
    uint256 amount;
}

Ylem structs map to the ABI type "tuple". For more information on how Ylem types map to ABI types see Mapping Ylem to ABI types in the Ylem documentation.

Structs are therefore encoded and decoded as tuples. So the struct we defined above, MyStruct, maps to the tuple (address,uint256) in terms of the ABI.

Let's see how this works in a contract:

pragma solidity =1.1.2;


contract Test {
    struct MyStruct {
        address addr;
        uint256 amount;
    }
    function f(MyStruct memory t) public pure {}
}

The ABI of the f function in this contract is:

{
  "inputs": [
    {
      "components": [
        {
          "internalType": "address",
          "name": "addr",
          "type": "address"
        },
        {
          "internalType": "uint256",
          "name": "amount",
          "type": "uint256"
        }
      ],
      "internalType": "struct Test.MyStruct",
      "name": "t",
      "type": "tuple"
    }
  ],
  "name": "f",
  "outputs": [],
  "stateMutability": "pure",
  "type": "function"
}

which reads: The function f takes 1 input of type tuple with two components of type address and uint256.