Lesson 2: "SimpleStorage" vs "simpleStorage"

[oceanwillo]

My understanding is that "SimpleStorage" is the type of variable while "simpleStorage" is the name we assigned to the variable.

However, I think my thinking is flawed since when I researched the types of solidity variables none of them were "SimpleStorage".

Is "SimpleStorage" syntax of some kind? Why does it seem like we use that phrase specifically as an identifier?

Here is the code below:

contract StorageFactorty {

    SimpleStorage[] public simpleStorageArray;



    function createSimpleStorageContract() public {
        //in order to let the storage factory know what the Simple Storage code looks like I will copy and paste the code from the other file
        SimpleStorage simpleStorage = new SimpleStorage();
        simpleStorageArray.push(simpleStorage);


    }


    function sfStore(uint256 _simpleStorageIndex, uint256 _simpleStorageNumber) public 
    {
        //To interact witj a contract you will need its Adrees and its ABI - Application Binary Interface
        SimpleStorage simpleStorage = simpleStorageArray[_simpleStorageIndex];
        simpleStorage.store(_simpleStorageNumber);
    }

    function sfGet (uint _simpleStorageIndex) public view returns (uint256){
        SimpleStorage simpleStorage = simpleStorageArray[_simpleStorageIndex];
        return simpleStorage.retrieve();
    }

[Nlferu]

Hello @oceanwillo

In this case our SimpleStorage is just TYPE, which is contract object containing all functions of SimpleStorage contract, which we have created earlier. When we are using simpleStorage we are just creating new variable with type SimpleStorage. This syntax is not solidity keyword of any kind you can change it into whatever you want as you have created SimpleStorage contract, so its up to you how you will name it. Is it clear for you now?

[oceanwillo]

So, essentially if I had named the object that contained all the functions "ComplexRacing" I would use ComplexRacing as the type to create new variables within the contract?

[Nlferu]

@oceanwillo Yes, it is working for objects like contracts or even structs etc.

Some example of struct object:

    struct Certificate {
        string s_tokenIdToURI;
        address s_tokenIdToBorrower;
        uint256 s_tokenIdToBorrowStart;
        uint256 s_tokenIdToBorrowFinish;
    }
 mapping(uint256 => Certificate) private certs;

 function mintNFT() external {
        Certificate storage cert = certs[newTokenId];
}

[oceanwillo]

Thank you, I really appreciate it.

[alymurtazamemon]

@oceanwillo I think you didn't see this type while searching Contract Types in Solidity