lesson-14 questions about CONSTRUCTOR.

[TimeKeyRoll]

Hey! As I understand address vrfCoordinatorV2 (green) is the address of VRFCoordinatorV2Interface (red)..Is that right ?
If yeah then how we are fetching vrfCoordinatorV2 from VRFCoordinatorV2Interface.

[alymurtazamemon]

@TimeKeyRoll Good Question, See this green address vrfCoordinatorV2 is the address of vrf that we will pass from our deploy scripts. Now this yellow VRFConsumerBaseV2 is an abstract contract that we are inheriting (the second yellow above it), why are we inheriting it, because it will insure that the contract that will use the VRF must inherit the fulfillRandomWords functions in a contract (you can see details of implementation inside that by holding control + click on it). That's why we are passing the vrf address to it as well, and the same address we will pass to interface like this VRFCoordinatorV2Interface(vrfCoordinatorV2); so that we can access the functions of that contract as well.

[TimeKeyRoll]

Very nice explanation. Okay got it.
However just wondering where it's written or mentioned that the 'vrfCoordinatorV2' is the address of 'VRFCoordinatorInterface'. I mean address of 'VRFInterfaceV2' could be anything. Right!? BUT we are mentioning specific 'vrfCoordinatorV2' as the address. So how do we know or where do we check from to confirm it is the same address as we are mentioning !?Hope my question is making sense here. :)

[krakxn]

constructor(address vrfCoordinatorV2)

This is just a parameter of our constructor; we are not fetching it or anything from the packages (the name is just for its aptness--you can even put TimeKeyRoll).

Since, you know that when we deploy the contract--where this code snippet is from--in a deploy script, we provide the args which represent the parameters of the constructor (of the contract).

Thus, it can be any address syntactically; however, logically speaking, for our code to work as intended, we should provide it a VRFCoordinator address in the deploy script.

So, it is just an address type parameter which should be provided a VRFCoordinator address in the deploy script.

[TimeKeyRoll]

This is the answer to my question. Thank you very much Indeed.

[krakxn]

Good luck!