Struct – How to Call Functions with Large Struct Parameters in Solidity

stackstruct

Let's say I have the following code:

// This is in a separate imported interface.
interface MyInterface{
  struct MyStruct {
    uint256 one;
    uint256 two;
    // . . .
    uint256 sixteen;
  }
}

// This is in a separate contract
function doSomething(MyInterface.MyStruct a) public{

How could I doSomething from another contract? Right now, if I create a struct in my other contract:

MyStruct patrickStruct = (one, two, three, ..., sixteen);

I will get:

Compiler run failed
CompilerError: Stack too deep when compiling inline assembly: Variable value0 is 2 slot(s) too deep inside the stack.

How do I fix this?

Best Answer

You wouldn't be able set the variable in storage, even the whole struct as a variable, you'd have to set individual subsets of the variables into storage. This way they can be popped off the stack.

Related Solutions

Passing Storage Structure Addresses Between Solidity Contracts

Instinctively, I believe that the only solution is to pass the structure to the function "by address"

You cannot access the physical addresses of storage variables (like you can with C), this is not allowed in Solidity. The address type is only used to refer to the addresses of other accounts (contract or external), and is not used to refer to memory addresses.

A work around would be to use a smart contract to store your data instead of a struct. This way you would be able to pass the address of the smart contract around instead of having to pass the data around. I've posted an example below:

contract Person {
    uint public age;
    uint public weight;

    function Person(uint _age, uint _weight) public {
        age = _age;
        weight = _weight;
    }
}

contract PersonHolder {

    address[] public people; // Could use Person[] here

    function addPerson(uint age, uint weight) public {
        people.push(new Person(age, weight));
    }

    function getPerson(uint index) public view returns (Person) {
        require(people.length > index);

        return Person(people[index]);
    }
}

Ethers.js Struct Parameter – How to Call Function with Struct Parameter

For struct, you use an object to insert argument:

const data = {
    value: 100,
}
const tx = await test.double(data);
console.log(tx);

I tried and got the output:

[ 
BigNumber { value: "200" }, 
value: BigNumber { value: "200" } 
]

Best Answer

Related Solutions

Passing Storage Structure Addresses Between Solidity Contracts

Ethers.js Struct Parameter – How to Call Function with Struct Parameter

Related Topic