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Version: Current

Contract Interface FungibleToken

contract interface FungibleToken {

totalSupply: UFix64
}

The interface that Fungible Token contracts implement.

Interfaces​

resource interface Provider​

resource interface Provider {
}

The interface that enforces the requirements for withdrawing tokens from the implementing type.

It does not enforce requirements on balance here, because it leaves open the possibility of creating custom providers that do not necessarily need their own balance.

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resource interface Receiver​

resource interface Receiver {
}

The interface that enforces the requirements for depositing tokens into the implementing type.

We do not include a condition that checks the balance because we want to give users the ability to make custom receivers that can do custom things with the tokens, like split them up and send them to different places.

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resource interface Balance​

resource interface Balance {

balance: UFix64
}

The interface that contains the balance field of the Vault and enforces that when new Vaults are created, the balance is initialized correctly.

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Structs & Resources​

resource Vault​

resource Vault {

balance: UFix64
}

The resource that contains the functions to send and receive tokens. The declaration of a concrete type in a contract interface means that every Fungible Token contract that implements the FungibleToken interface must define a concrete Vault resource that conforms to the Provider, Receiver, and Balance interfaces, and declares their required fields and functions

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Functions​

fun createEmptyVault()​

func createEmptyVault(): Vault

Allows any user to create a new Vault that has a zero balance

Returns: The new Vault resource

Events​

event TokensInitialized​

event TokensInitialized(initialSupply UFix64)

The event that is emitted when the contract is created

event TokensWithdrawn​

event TokensWithdrawn(amount UFix64, from Address?)

The event that is emitted when tokens are withdrawn from a Vault

event TokensDeposited​

event TokensDeposited(amount UFix64, to Address?)

The event that is emitted when tokens are deposited into a Vault