When you deploy a compiled smart contract to an Ethereum-like blockchain like RSK, your transaction includes the compiled bytecode, including the constructor code. An example, if you want to deploy Counter.sol: pragma solidity >=0.5.0 <0.6.0; contract Counter { uint public counter…

These days I am practicing programming smart contracts in Solidity using TDD. There are several projects I am working on: some DeFi projects, a programmatic faucet, user login and onboarding, personal notes, some games. One of the projects already has something to show: I have been able to upload (image)…

Based on an idea by bguiz published in RSK reseach forum: Crazy Idea: New opcodes for relational DB like data reads and writes, I was writing Solidity code to explore an alternative implementation in an Ethereum-like blockchain. I don’t add opcodes because these are scarce, and adding them could broke…

These years I was programming a log, using TDD (Test-Driven Programming), to keep me trained in design and developer skills. To me, TDD is a great workflow to discover emergence design solutions, to simple and complex domains. One of my preferred domains is blockchain, and I wrote tons of code…

In an Ethereum-like blockchain (like RSK or my personal project BlockchainJ) the smart contracts have a linear storage, composed by cells thafied by a key. In case of storage, the key is a data word of 32 bytes (a kind of unsigned big number) and the value is also a…

I’m very proud of my favorite personal project BlockchainJ: build a Blockchain in Java, from scratch, using TDD (Test-Driven Development). Previous posts: Building a Blockchain: Introduction Building a Blockchain: Main Entities Building a Blockchain: Serialization Building a Blockchain: Key Value Stores Building a Blockchain: Subroutines in the Virtual Machine Building a Blockchain: Towards Beam Synchronization…

Some months ago, I wrote about Command Line Tools for RSK Node; now those tools are included in the latest RSKJ release (under the package with name co.rsk.tools.cli). Using a local testnet database, I exported 5000 blocks with the command: java -cp <rsk.jar> co.rsk.cli.tools.ExportBlocks 718000 722999 --testnet > testnetblocks.txt These…

Suppose that you have an online web site, social network, or game. Your users connect with your server(s) using a mobile, web or desktop client application. Each user has a nickname, and should provide credentials to initiate a session with your server. Now, you want to give them tokens, as…

I’m very enthusiastic about my personal open source project BlockchainJ, a blockchain written in Java using TDD. To me, it’s very interesting (and a lot of fun) to design, write and explore ideas and code using the Test-Driven Development workflow. I think that you can understand any problem if you…