Hello, everyone!
This week your host will be me, @thewizardlucas ✨
I'm a Brazilian Software Engineer, currently in… twitter.com/i/web/status/1…

I'm currently writing a book about JavaScript testing, which you can find at this tweet's link, and I often write a… twitter.com/i/web/status/1…

100% code coverage does not exist.

The only way you can make it impossible for your software not to make certain m… twitter.com/i/web/status/1…

In his brilliant article named "Why Most Unit Testing is Waste" (rbcs-us.com/documents/Why-…) James O'Coplien explains… twitter.com/i/web/status/1…

"I define 100% coverage as having examined all possible combinations of all possible paths through all methods of a… twitter.com/i/web/status/1…

"Anything else is a heuristic about which absolutely no formal claim of correctness can be made."

Tests can't prove that your software doesn't have bugs, they can only prove it _has_ bugs.

On the other hand, Type… twitter.com/i/web/status/1…

In this talk (one of my favourite talks ever), @rtfeldman explains in more detail how to use types to make impossib… twitter.com/i/web/status/1…

Contrary to what most people think, Test Driven Development is not about tests.
It's about taking small iterative s… twitter.com/i/web/status/1…

Another misconception that people have is that they should always repeat the TDD cycle (failing, passing, refactor)… twitter.com/i/web/status/1…

The more confident you are, the more thorough should be the tests you create, and the bigger should be the chunks o… twitter.com/i/web/status/1…

One of the things that has made me the most productive in my career was to learn how to properly use a terminal.
To… twitter.com/i/web/status/1…

A few things have changed in my stack since then, but, currently, here are the most important tools I've been using… twitter.com/i/web/status/1…

As far as Vim plugins go, I don't use many. The ones I think are the most useful are FZF (github.com/junegunn/fzf.v…)… twitter.com/i/web/status/1…

You can find my dotfiles with these configs at github.com/lucasfcosta/do….

These files have been wanting my attention… twitter.com/i/web/status/1…

The best way to review PRs is to:
⭐ Assume that there is _always_ something that can be improved and that your job… twitter.com/i/web/status/1…

Akin’s Laws of Spacecraft Design (spacecraft.ssl.umd.edu/akins_laws.html) are one of the most useful pieces of wisdom for any engi… twitter.com/i/web/status/1…

1. Engineering is done with numbers. Analysis without numbers is only an opinion.

8. In nature, the optimum is almost always in the middle somewhere. Distrust assertions that the optimum is at an extreme point.

9. Not having all the information you need is never a satisfactory excuse for not starting the analysis.

20. A bad design with a good presentation is doomed eventually. A good design with a bad presentation is doomed immediately.

33. (Patton's Law of Program Planning) A good plan violently executed now is better than a perfect plan next week.

Given that my twitter handle is @thewizardlucas, I couldn't help but love something as magical as streams 💖

Throug… twitter.com/i/web/status/1…

🤔Why I love streams

I love streams because I don’t like software.

I always try to build less software. Less softw… twitter.com/i/web/status/1…

❓How can streams help build less software?

Streams help us writing less software because they allow programs to co… twitter.com/i/web/status/1…

By enabling inter-process communication, streams encourage software to be smaller and sometimes can even prevent so… twitter.com/i/web/status/1…

📚What are streams?

In the same way that a river has a stream of water, programs have streams of data. Moreover, ju… twitter.com/i/web/status/1…

⚙️How do streams work?

Streams can be used to pass data into programs and to get data out of them.

In UNIX, progr… twitter.com/i/web/status/1…

There are three different standard streams:

* standard input ➡️the stream which feeds your program with data
* sta… twitter.com/i/web/status/1…

The cat program, for example, uses the stdin to receive input from your keyboard and the stdout to send it out.

Da… twitter.com/i/web/status/1…

When you know what each stream does, you can connect multiple programs through them. pic.twitter.com/prJDwt6lm1

What if I told you that your terminal is not "really" a terminal❓

If you are not a hardcore time-traveller, what y… twitter.com/i/web/status/1…

These emulators provide you with an interface to interact with the Linux TTY driver. The TTY driver is responsible… twitter.com/i/web/status/1…

Each TTY has its own stdin, stdout, and stderr streams connected to it. These are the streams provided to programs… twitter.com/i/web/status/1…

Like everything in UNIX, the tty is a file. Each instance of a terminal emulator has a different tty file associate… twitter.com/i/web/status/1…

To find out which tty is associated with a terminal window you can use the tty command. pic.twitter.com/wp6QOhBOFZ

When you open a new terminal window, its streams will point to the connected TTY. pic.twitter.com/7VyQwyXiOg

To complement the two threads about #unix #streams that I've done today, here go a few related links that I'd recom… twitter.com/i/web/status/1…

К сожалению, далеко не ламповая редакция подвела нас в очередной раз 😭

Ну ничего, ждём следующей недели...

Today, a little bit about lambda calculus, to complement one of my favourite talks ever, this one, at HolyJS 2018:

youtube.com/watch?v=rqZuNA…

A long time ago, a guy called Leibniz had a dream: he wanted to solve all problems using logic.

His dream was to b… twitter.com/i/web/status/1…

If you would like to hear straight from Leibniz himself, this is what he said:

"If controversies were to arise, th… twitter.com/i/web/status/1…

"For it would suffice for them to take their pencils in their hands and to sit down at the abacus, and say to each… twitter.com/i/web/status/1…

And for a long time, people have tried to do create formal ways of expressing computation and solving problems. Her… twitter.com/i/web/status/1…

Today, most of us already know one way of expressing computations: through the use of Turing Machines.

The other w… twitter.com/i/web/status/1…

To this day, learning lambda calculus can be very helpful for one to learn functional programming properly. Not at… twitter.com/i/web/status/1…

Continuing the thread about Lambda Calculus from yesterday!

In this one, we'll go through the very basics and talk… twitter.com/i/web/status/1…

Everything in Lambda Calculus is an expression, which means that everything must evaluate to a value.

There are, h… twitter.com/i/web/status/1…

➡️Identifiers are simply that: identifiers. They identify certain values by giving them a “name”, just like our mod… twitter.com/i/web/status/1…

➡️Abstractions are perhaps the most iconic kind of lambda expression, they define what we call functions or, more a… twitter.com/i/web/status/1…

The ID in the beginning of that abstraction is called the metavariable. The metavaraible is the variable that is go… twitter.com/i/web/status/1…

➡️ Applications denote function invocation. If you have a function A you can say you’re calling it with B by writin… twitter.com/i/web/status/1…

➡️Grouping exists for the sake of disambiguation. We use these parentheses around the expressions we want to group… twitter.com/i/web/status/1…

Writing software is easier than writing books because you don’t have to build an entire product before you can sell… twitter.com/i/web/status/1…

The fact that you can ship software several times a day at zero-cost allows you to make fewer assumptions when buil… twitter.com/i/web/status/1…