Best way to create a Vault to put Tokens in it? (others call it Pool)

[NaDasai]

Discord user ID

ibuidl

Describe your question in detail.

I want to create a Vault/Pool where when the users pays (let's say in APT) for a service, the Tokens are added to the Vault/Pool.
After that the one that provided the service would go and claim those tokens.
I tried with this, but I'm not sure it's the best way to do it:

    struct Pool has key {
        coins : coin::Coin<AptosCoin>,
    }

then

        let pool = borrow_global_mut<Pool>(@module_addr);
        let coin = coin::extract(&mut pool.coins,amount);

What error, if any, are you getting?

No response

What have you tried or looked at? Or how can we reproduce the error?

No response

Which operating system are you using?

macOS

Which SDK or tool are you using? (if any)

Rust SDK

Describe your environment or tooling in detail

No response

[kshitijc1506]

You're on the right track with Coin. Here's a full example that supports both Coin and FA.

[NaDasai]

1/ About this part:

    #[resource_group_member(group = aptos_framework::object::ObjectGroup)]
    struct FARewards has key {
        rewards: SmartTable<String, FALockBox>,
    }

Can you explain what's the resource_group_member about?
And the SmartTable is it the equivalent of KeyValueStore in Rust? And when you use a "smart" table, how is it different from normal one?

2/ I guess this ise like the one I used:

    struct CoinRewardPool<phantom CoinType> has key {
        project: String,
        coins: Coin<CoinType>,
        distribution_amount: u64,
        claimed: vector<address>
    }

Why is added?

3/ So this is the FA (what's FA btw?) you mentionned:

    struct FALockBox has copy, drop, store {
        pool: Object<FungibleStore>,
        distribution_amount: u64,
        claimed: vector<address>
    }

When do you use a FungibleStore and why do we use Object?

[kshitijc1506]

(1) that is the resource group annotation, it treats those resources as a single resource in global storage / stores them in a single storage slot.

SmartTable is designed to be more flexible and gas efficient than a regular table. read more here.

(2) not sure what you mean by this question

(3) FA is the Fungible Asset Standard. it's the newer standard for fungible tokens and uses the aptos object model as its building blocks.

[NaDasai]

(1) Is there a reason why we should store in a single slot?
(2) sorry for got to copy past: why is used here?
(3) So it's better recommend for the Vault/pool? If yes, why?

[kshitijc1506]

for (1) you can read the AIP I linked, has all the details :)

for (2) and (3), since we're in the middle of migration, it makes sense to support both. read more about the migration here.