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iterable-mapping

Smart contracts created with Solidity provide a mapping type for storing key-value pairs. This mapping type is useful for storing or reading value values ​​for a specific key. However, it does not provide an iteration function to retrieve all the lists stored in the mapping, or to sequentially read the value by repeating the list.

In this article, let’s look at a pattern that iterates lists stored in a mapping. You’ll also notice some things to keep in mind when adding a new list to a mapping or deleting an existing list.

Non-iterable smart contract with only mapping

Let’s look at a smart contract example that includes a mapping that has an address type as key and a byte32 type as…


@Foundation X Night

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Foundation X Night 행사 모습

On July 20th, Foundation X Night event was held at Le Meridien Hotel in Gangnam, Seoul. At the event, There were many prominent ICO companies, Blockchain investors, exchanges and Venture Capitals for exchanging informations and professional networking.

The Rayon Protocol team arrived early and to prepare their first official announcement. Despite arriving early to rehearse, we felt a huge interest from people as there were a lot of people were already present even before the event started. Moreover, we could see many professionals talking to each other for sharing their stories and information through active networking.

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Jay Hwang @ Foundation X

Founded in March by experts with successful business and exit experiences, Foundation X is an accelerator for blockchain tech startups. Future play partner as well as a CEO of Foundation X — Jay Hwang — highlighted the potential and future of the blockchain by giving the participants a great speech. …


The Rayon team was invited to present and participate in a panel discussion during the Block72 (https://block72.io/) Meetup in Seoul on Aug. 16, 2018 which took place at Jam2Go in Gangnam.

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This Seoul meetup was the fourth “Blockchain x Industry” themed meetup hosted by Block72, where the topic for this fourth session was “Blockchain x Financial Services”. Teams who were invited to participate in the meetup included:

Rayon Protocol — decentralized service protocol to build a lending marketplace (https://www.rayonprotocol.io/)

Libra Credit — a crypto lender / decentralized lending ecosystem (https://www.libracredit.io/)

Peoplefund — a Korean P2P lender (https://www.peoplefund.co.kr/)

MyToken — a crypto asset management platform (https://www.mytoken.io/) …


@Foundation X Night

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Foundation X Night 행사 모습

7월 20일 강남 르메르디앙 호텔에서 국내외 유망한 ICO 업체와 투자자, 거래소, VC 들이 다수 참여하는 Foundation X Night 행사가 개최되었습니다.

Rayon Protocol 팀도 일찌감치 도착하여 첫 공식 발표를 준비 및 연습을 했습니다. 리허설을 위해 일찍 도착했음에도 불구하고, 미리 참석한 사람들이 많아서 행사에 대한 관심과 참여를 느낄 수 있었습니다. 또한 곳곳에서 활발한 네트워킹을 통해 서로의 의견을 교환하는 모습도 자주 목격할 수 있었습니다.

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Foundation X 황성재 (Jay Hwang) 대표

Foundation X는 성공적인 사업과 엑시트 경험을 가진 전문가들에 의해 지난 3월에 설립된, 블록체인 관련 스타트업을 육성하는 엑셀러레이터입니다. 퓨처플레이 파트너이자 Foundation X의 황성재(Jay Hwang) 대표는 이 날 연설을 통해 블록체인이 가지고 있는 잠재성과 미래를 강조했습니다.

이어서 라이즈(LYZE), 프랫지캠프(Pledgecamp), 캐스토(Casto), 아이스 프로토콜(ICE Protocol)과 레이온 프로토콜(Rayon Protocol)과 같이 처음으로 공식석상에서 발표한 프로젝트들과, Token Sales를 시작한 마인드.AI(Mind.AI), 크립톤(Crypton), 캐리 프로토콜(Carry Protocol) 등의 발표가 이어졌습니다. …


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Jun Woo Ji of Rayon Protocol has been appointed as a Nebulas Korea Ambassador

Nebulas launched its Eagle Nebula 1.0 mainnet in 1Q18. Nebulas launched & operated the first season of its Nebulas Incentive Program from May 7, 2018 ~ July 2, 2018 in order to encourage the development of Nebulas DApps as well as to further build the Nebulas ecosystem. The Nebulas Incentive Program is held across 8 weeks and winners are announced & awarded on a weekly basis.

Total prize money was 460,000 NAS(KRW4.1 bn equivalent, assuming NAS price as at May 14, 2018), which was particularly large to draw sufficient attention from developers. “Even if you don’t win or get ranked near the top, you were able to receive 100 NAS as a reward for simply developing a new Nebulas DApp, so I thought I should participate in the program no matter what. …


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Let’s build an environment for developing DApps that run on the EOS platform.

For our reference, we used the local environment set-up in the official EOSIO wiki document.

EOSIO Components

EOSIO has three components.

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  • nodeos : node component that manages blockchain
  • keosd: component that manages wallet
  • cleos: CLI that controls blockchain and wallet

Install EOSIO

In this article, we explain our topic based on MaxOS Darwin 10.12.

First, please clone the source code from EOSIO git

$ git clone https://github.com/EOSIO/eos --recursive

Xcode and homebrew should be installed to build the source code. …


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We will explore the relationship between account, wallet and key pairs that are used in EOS.IO.

We can see their behavior by running the ‘cleos’ command.

For our reference, we used the account and permission document in the official EOS.IO wiki.

Wallet

Wallet is where key pairs are stored. Wallets can have state of lock and unlock, and needs to have passwords entered to be unlocked. Wallets are managed by ‘keosd’ commands and the values can be verified through ‘cleos’ commands.

Account

This is an identifier that users in blockchain can read. It is used when a transaction is executed and released. …

RayonProtocol

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