自己紹介

こんにちは、私はグウェン(https://twitter.com/gwenskiesHere)です。今日、ERC223についてを話し合いましょう。

ERC223とは

DexaranはERC223スタンダードを言い出した。ERC223トークンスタンダードではトークンを譲すことをetherトランザクションのように可能にするそして、手がけないトランザクションを手がけます。これはERC20のトランザクションの誤りを繕いますから、fundsを無くなってない。ERC223はERC777と使うことができます。ERC223のロジックはERC777と比較して簡単です。ERC223はless error-prone codeを保証います。ERC223トークンはきみの実装を頼る。

ERC223を使用する理由

To stop the continuous loss of tokens. There are reports of users losing a lot of ERC20 tokens just because they sent the tokens to the wrong contract.
To make the transfer mechanism of tokens similar to that of transferring Ether.
To correct the inability of handling incoming token transactions for non-supported tokens.
To eradicate one step out of the two-step process of transactions that happens in a token transfer.

ERC223 Use Case

Trust Wallet

ERC223Interfaceのコード

ERC223Interface.sol

pragma solidity ^0.4.11;

contract ERC223Interface {
    uint public totalSupply;
    function balanceOf(address who) constant returns (uint);
    function transfer(address to, uint value);
    function transfer(address to, uint value, bytes data);
    event Transfer(address indexed from, address indexed to, uint value, bytes data);
}

ERC223のコード

ERC223はERC223Interfaceの関数をinheritする。

ERC223.sol

pragma solidity ^0.4.11;

import './ERC223_interface.sol';
import './ERC223_receiving_contract.sol';
import '././SafeMath.sol';

/**
 * @title Reference implementation of the ERC223 standard token.
 */
contract ERC223Token is ERC223Interface {
    using SafeMath for uint;

    mapping(address => uint) balances; // List of user balances.
    
    /**
     * @dev Transfer the specified amount of tokens to the specified address.
     *      Invokes the `tokenFallback` function if the recipient is a contract.
     *      The token transfer fails if the recipient is a contract
     *      but does not implement the `tokenFallback` function
     *      or the fallback function to receive funds.
     *
     * @param _to    Receiver address.
     * @param _value Amount of tokens that will be transferred.
     * @param _data  Transaction metadata.
     */
    function transfer(address _to, uint _value, bytes _data) {
        // Standard function transfer similar to ERC20 transfer with no _data .
        // Added due to backwards compatibility reasons .
        uint codeLength;

        assembly {
            // Retrieve the size of the code on target address, this needs assembly .
            codeLength := extcodesize(_to)
        }

        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        if(codeLength>0) {
            ERC223ReceivingContract receiver = ERC223ReceivingContract(_to);
            receiver.tokenFallback(msg.sender, _value, _data);
        }
        emit Transfer(msg.sender, _to, _value, _data);
    }
    
    /**
     * @dev Transfer the specified amount of tokens to the specified address.
     *      This function works the same with the previous one
     *      but doesn't contain `_data` param.
     *      Added due to backwards compatibility reasons.
     *
     * @param _to    Receiver address.
     * @param _value Amount of tokens that will be transferred.
     */
    function transfer(address _to, uint _value) {
        uint codeLength;
        bytes memory empty;

        assembly {
            // Retrieve the size of the code on target address, this needs assembly .
            codeLength := extcodesize(_to)
        }

        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        if(codeLength>0) {
            ERC223ReceivingContract receiver = ERC223ReceivingContract(_to);
            receiver.tokenFallback(msg.sender, _value, empty);
        }
        emit Transfer(msg.sender, _to, _value, empty);
    }

    
    /**
     * @dev Returns balance of the `_owner`.
     *
     * @param _owner   The address whose balance will be returned.
     * @return balance Balance of the `_owner`.
     */
    function balanceOf(address _owner) constant returns (uint balance) {
        return balances[_owner];
    }
}

ERC223 Github: https://github.com/Dexaran/ERC223-token-standard

sources:
https://www.cointelligence.com/content/comparison-erc20-erc223-new-ethereum-erc777-token-standard/
https://medium.com/koinbros/what-are-erc20-and-erc223-tokens-307badcca5a