第3节：设计module

接下来我们将编写一个token，并逐步完善细节，本节将定义token的接口。

Code

我们准备发型一个Token，本节仅定义接口

module NamedAddr::BasicCoin {
    struct Coin has store {
        value: u64
    }

    struct Balance has key {
        coin: Coin
    }

    /// Publish an empty balance resource under `account`'s address. This function must be called before
    /// minting or transferring to the account.
    public fun publish_balance(account: &signer) { .. }

    /// Mint `amount` tokens to `mint_addr`. Mint must be approved by the module owner.
    public fun mint(module_owner: &signer, mint_addr: address, amount: u64) acquires Balance { .. }

    /// Returns the balance of `owner`.
    public fun balance_of(owner: address): u64 acquires Balance { .. }

    /// Transfers `amount` of tokens from `from` to `to`.
    public fun transfer(from: &signer, to: address, amount: u64) acquires Balance { .. }
}

• move里面的module没有storage，每个地址可以有module（code）和resources（value）；
• 每个地址下面的resource都是个mapping，这意味着每种类型只能有一个值；
• 上面的代码中，Balance是NameAddr下面的resource，它存储每个地址持有的数量。

Note

只有修饰为public(script)的函数才可以被直接调用，function可见性，点击查看

public(script) fun transfer(from: signer, to: address, amount: u64) acquires Balance { ... }

状态对比：move

状态对比：solidity