Writing a C program to process files is easy when you already know what files you'll operate on and what actions to take. If you "hard code" the filename into your program, or if your program is coded to do things only one way, then your program will always know what to do. But you can make your program much more flexible if it can respond to the user every time the program runs. Let your user tell your program what files to use or how to do things differently. And for that, you need to read the command line.

In our team at Rakuten, we have been using Elm1 in production for almost two years now. This post is about our story, the lessons we learned, and our likes and dislikes. This post is quite long so if you prefer to see an overview, feel free to jump to the index. Everything started in the Berlin branch of Rakuten during the summer of 2017. We were maintaining a medium-size single-page application written in Vanilla JavaScript when things started going out of control.

Let's actually whiteboard some code.

B-Trees are not boring, after all

Reading code is more important than writing code. But, more important than reading is reasoning about code.

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Or in other words, how to build intention revealing APIs through encapsulation, a practical guide.

“Can I still use…” provides the latest information on the deprecation of upcoming browser APIs [satire].

How can we bring back the love of code

Through a podcast, technologist Marianne Bellotti takes listeners on her journey to write a new language from scratch. It's no easy task, but the host has fun while shedding light on the tools programmers use.

Last week I showed a few ways in which to improve the performance of a Haskell intepreter for a register machine. In this post, we start with the exact same bytecode (same register language, same compiler) and show how to use a much slower language (Clojure) to end up with a much faster interpreter.This series is based on Neil Mitchell's talk "Cheaply writing a fast interpeter". The talk compares a number of approaches to writing an interpreter and tries to find a good balance between complexity and interpreter overhead.The following topics, while important, are out of scope:

How to use webhooks to build your subscription-based platform

One of the compelling aspects of modern SQL is the JSON support built into modern engines, including Postgres. The documentation is well done, but I need examples to motivate my understanding of wh…

Chaos Toolkit

Visualize binary protocols by building parsers in Elixir.

Learn what parser combinators are, what they are made of, and how to make your own CSV parser using NimbleParsec, a parser combinator library written in Elixir.

Papercups is an open-source live chat widget. Chat with your customers to improve conversions and customer satisfaction.

The Reg chats with co-founder Sven Efftinge

I recently rewrote a service that was on AWS API Gateway and Lambda in Elixir and apparently that intrigued some people, so I decided to do…

Phoenix is a web framework for the Elixir programming language that gives you peace of mind from development to production

p5.js a JS client-side library for creating graphic and interactive experiences, based on the core principles of Processing.

Website for Elixir

Structural code search and replace for ~every language.

Build cross-platform desktop apps with JavaScript, HTML, and CSS.