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Calculus made easy With all the trend about LLM, maybe time to dust up our math skill in high school.

validates_email_format_of Validate e-mail addreses against RFC 2822 and RFC 3696 with this Ruby on Rails plugin and gem.

The Simple Beauty of XOR Floating Point Compression I recently implemented a small program to visualize the inner workings of a scheme that compresses floating point timeseries by XORing subsequent values. The resulting visualizations are quite neat and made it much easier for me to understand this beautiful algorithm than any of the explanations that I had previously encountered.

A simple query with a big problem Render.com staging pipeline got blocked due to what looked like a simple query SELECT e.id FROM events e JOIN postgres_dbs db ON (e.data ->> ‘serviceId’) = db.database_id LIMIT 1; Can you spot what’s wrong? Let’s read

How macOS opens a file in the correct app One of feature of Mac is it can detect the right app to open a file, even without a file extension. How did it works and how it evolve

Can You Grok It – Hacking together my own dev tunnel service Lets learn how to re-create a service similar to ngrok by re-using existing software such as nginx and openssh. There is also a great repository for these tunneling softwares

crystal ruby a gem that allows you to write Crystal code, inlined in Ruby. All you need is a modern crystal compiler installed on your system.

PythonMonkey A Mozilla SpiderMonkey JavaScript engine embedded into the Python VM, using the Python engine to provide the JS host environment.

madge is a developer tool for generating a visual graph of your module dependencies, finding circular dependencies, and giving you other useful info.

Using Multiple GitHub Accounts If you share laptop for home and work, or doing consultant for clients, you probably know the hassle of using different github account. This short guide help you configure just that, to make your life easiser by having git automatically load the right account based on directory.

pid-controller explainer A PID controller is a way to solve problems with the following formulation: You can change some input to the system, called the process variable You have a sensor which monitors something about the system You want the sensor measurement to be close to some target value, called the set point The PID controller is a good way to decide what the...

Linux networking This is somewhat a very low level. But recently I found I had not enough knowledge to understand networking at a very fundamental level. What exactly happen when we make a request, how the tcp connection is open, how the package is sent. how it picks which ethernet interface to send to? So I decide to google around and found this. I...

excelize Go language library for reading and writing Microsoft Excel™ (XLAM / XLSM / XLSX / XLTM / XLTX) spreadsheets

pg_basebackup Since Postgres 12, it has built-in support to take a base backup of a PostgreSQL cluster. If you have been glueing together pg_dump, pg_restore, etc you will love this tool too. Pair it with an optinal compression setting to get the best compression rate.

doltgresql Imagine a Postgres with git style log, diff, branch, and merge functionality. This is just that. The company behind it originaly released a MySQL flavored, but now they are taming Postgres.

automq a cloud-native, serverless reinvented Kafka that is easily scalable, manage-less and cost-effective. It uses Object storage(s3, gcs) as the main storage. Using EBS for durable cache layer to accelerate write. It’s 100% compatible with Apache Kafka greater than 0.9.x and not lose any good features of it, but cheaper and better.

drawdb robust and user-friendly database entity relationship (DBER) editor right in your browser. Build diagrams with a few clicks, export sql scripts, customize your editor, and more without creating an account.

glimmer a DSL framework to build GUI app in Ruby. It contains a DSL engine to express he GUI, and a data binding lib to sync GUI with model attributes bidirectionally.