Maurício Szabo

Goodbye, Chlorine. And welcome, Lazuli!

So, if you’re not familiar with Chlorine, or any of my tooling, let me get you a refresher. If you don’t want to read it all, the TL;DR; is – Chlorine is a Socket REPL plug-in for the Clojure, and ClojureScript languages. It also supports nREPL, although to a lesser extend, and it works on the Atom editor. It also contains a VSCode version called Clover, and I tried to port it to NeoVIM and I called it Clematis.

And now, it’s gone.

For historical reasons, I wanted to rename the project for a while – so that Chlorine would stay as a “socket REPL for the Atom editor” and the new plug-in would be the “Chlorine:Next” or something like this. I tried to like the name Alya, but in the end I never did…

… and then, I stopped working with Clojure. Like, at all. For a while I haven’t touched a single line of Clojure code, although I still use ClojureScript on my personal plug-ins. But ClojureScript have a weird problem – I can’t develop two plug-ins written in ClojureScript at the same time, so I need to compile everything, except for one, plug-in for “release”. Which is annoying to say the least, so that’s why I started the “Star Ring” metapackage – to make all plug-ins a “single, unified codebase”. Unfortunately, this have its own fractal of problems that I won’t discuss now.

So not that I’m now working with Ruby, I needed better tooling for Ruby otherwise I would go crazy. Leaving the “REPL-Driven Development” of Clojure behind is a nightmare, because it’s such a great tool and it somehow “grows” in you in such a way that you can’t imagine working in a codebase when you can’t evaluate your code all the time. And that’s where Lazuli appears… but again, because of the problems with not being able to develop Lazuli and Chlorine at the same time, Chlorine’s development stalled… and I decided to stop working on it to work in Lazuli.
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By Maurício Szabo, ago

There is NO SUCH THING as COLOR FUNCTIONS!

I try to not mention other blogs, or posts, or things like that. Unfortunately, it is needed. So, here we are.

Some time ago, I found this what color is your function post. I though, originally, that the “color” there was supposed to be a metaphor for other stuff, kind of like how the post about Railroad Oriented Programming was just the Either monad in an easier to digest format.

Turns out… people started to use this argument to explain why some language/library is better than other. And that is weird, and wrong, for a simple reason: there’s no such thing as “color-based function”.

Ok, I’ll say it again: there is NO SUCH THING as color-based function. And I’ll go further: this whole post is a complete lack of understanding about types, and I’m speaking as someone that likes, and prefers dynamic-typed languages, so you can imagine how freaking wrong the original author is. So let’s dive into the types, shall we?

So, I’ll start with this innocent function: nothing “async” about it:

registerCallback(f: (p: number) => number): void {
  self.callback = f
}

For those that are not familiar with Typescript notations, this is basically a function that accepts another function, which the first argument is a number, and the return is a number. This registerCallback function (method, really) returns nothing, or void. So far, so good. The type of this function is ((p: number) => number) => void, or in Java’s notation, Function<Function<number, number>, void>.

Now, how can I convert ((p: number) => number) => void to ((p: number) => number) => number? Well, if you know anything about static type systems, you know that… well… you can’t. You actually can’t. It’s impossible. Nothing is compatible here. And, guess what? The same is true for Promise types.
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By Maurício Szabo, ago

Performance optimizations WITHOUT Reagent – part 3 (and probably final)

This is probably the last post about these improvements. At the last post, I showed how I threw every performance optimization I tried away (combine-leafs, other stuff, etc) just to throw it all away because React didn’t like what I did.

So, after a lot of time, I decided to do the horrible, insane thing that I did a lot more than I wanted – rewrite the rendering process of Chlorine to not use Reagent. The reason was actually quite simple: I wanted things to be simpler to implement, and honestly, Reagent was getting in my way. Like, A LOT.

Before I continue explaining the performance improvements that I am doing, I have to say something – in the first version of the rendering code (the one that I was trying to optimize at my last posts) I had a huge beginner’s luck – the actual rendering time is amazing for most cases, and while it is slow for some very specific situations, it’s actually not that bad; but there were also some weird trade-offs that I had to do and I cannot use them anymore.

The reason being, Chlorine started to become very strong in the customization code and “interactive renderers”. If you’re not aware, you can configure Chlorine to add custom commands and other amazing stuff, just by opening up a config file, writing some ClojureScript code, and you’re good to go. Unfortunately, also at the first versions of Chlorine, sometimes you would evaluate a code – let’s say a list of a thousand elements – and you get back only 10 or 20 elements. Worse yet, you would not get back a “List”, but an object called an “Incomplete List”. Which was not ideal, and basically made the whole “customize your editor” difficult to say the least.
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By Maurício Szabo, ago

Porting Clojure libraries to Ruby – Part 2

Last post I gave an introduction on how I’m working with GraalVM to port Clojure things to Ruby. Now, it’s time to handle the hard parts.

The first thing is – some stuff simply doesn’t work. Pathom3 (the library I wanted to port) depends on Guardrails, which requires core.async, which starts a thread pool, which GraalVM doesn’t like. At all.

And the second things is how to serialize some weird stuff like callbacks. So let’s start with the first part – how to make a “Pathom3 shared library” without GraalVM screaming at us
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By Maurício Szabo, ago

Porting Clojure libraries to Ruby

Since I started working with Ruby, in some situations I miss some of the Clojure libraries – especially killer ones like Pathom.

Unfortunately, rewriting the whole library in a different language is completely out of the question, especially because I will reintroduce some of the bugs that are already fixed, and will not have some of the more important features like parallel processing and other stuff.

But it’s not an “end of the world” situation. GraalVM have a very important feature that is to compile Java code to native, using what it’s usually called the “native-image” or, to be more precise, SubtrateVM. I also knew that you could generate shared libraries with this approach, but I never actually did anything and in my last attempts – every time I tried the only result I had was lots of frustrations and weird errors.

So that’s why I’m very proud and very surprised to announce that I have a Pathom working in Ruby right now.

But more on that later – it’s probably not yet ready to be used in production; but what I want to share is how I actually made it work, then challenges I faced (and how to handle them) and how can other people do the same. Finally, I am writing this post to make it easy for other people to do the same – honestly, the whole thing was awfully hard but not because it’s actually hard – but because the documentation is lacking so much that, at some times, I even though things I did were not possible.
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By Maurício Szabo, ago

Clojure, and Ruby

I’m gonna make a bold claim here. As a language, Clojure is much better than Ruby. But, as a means of working together with other people, Ruby can be better, and Clojure can be a nightmare.

Here’s the problem with this debate: in Ruby it’s easier to actually bootstrap something because of the Rails framework. Clojure doesn’t have anything like that, but the code tends to get less worse as time goes by – as a functional language where everything is immutable by default, there’s less “surface” that’s touched by a piece of code. For example, suppose you have a function – in Clojure, changing that function only affects callers of that function, whereas in a mutable language, the function can mutate an object/value and now everywhere that uses that same object can be affected.

Another reason, that might be counter-intuitive is because of the real framework itself. When an application grows, you might find that you need less constraints and more freedom to do stuff that was not defined originally. Unfortunately, if you are using Rails (or any other framework), this means that you have to find ways around the framework, because it’s a kind of an “all or nothing” – it’s not that easy to basically do something outside of it and then bring that into your workflow, into your web servers and things like that (for example, I once had to integrate a SQS message queue on Rails, to listen to some message and deliver a notification via websocket. It was such a bad experience that we did a Node.JS app that did just that).
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By Maurício Szabo, ago

The COMPLETE Liskov Substitution Principle

LSP (short for Liskov Substitution Principle, not for Language Server Protocol) is probably one of the least understood concept of the SOLID principles. So in this post, I want to actually address the complete principle, not just what people know.

Because of the “typed” nature of the LSP, I’ll try to use a language that people are familiar with, and that I can show in a playground somewhere: Typescript. Truth to be told, I am not a Typescript developer (nor do I actually like the language) so my code might be a little weird. Anyway, moving on:

What people know

The actual text is

Let Φ(x) be a property provable about objects x of type T. Then Φ(y) should be true for objects y of type S where S is a subtype of T.

This is actually hard to read, so people simplify, usually, with:

Objects of a superclass shall be replaceable with objects of its subclasses without changing behavior

Which is correct, but incomplete.
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By Maurício Szabo, ago

Last open-source improvements

For the last two months, I have been busy searching for a new job, unfortunately. But also, because of this, I was able to evolve on lots of projects that I have been working in a while. So in this quick post I want to explain a little bit what I did, what is happening, and hopefully somebody might be interested in some very interesting improvements.

First thins, I already wrote about Chlorine in my last post. This week I was able to remove all the dead code that I had in the previous version, and I’m closer than ever to publish a new version of that I will call “Version 2.0”. Unfortunately, this version will be lacking some features that the previous version had, and I’m not really sure if I’m going to add this back or not.

But the thing is, because the new Chlorine is more configurable and the config file is easier to write, I hope people can add these features in user-space, so I can decide later if I’ll re-include them or not (it’s always easier to add stuff than remove what people already depend on).
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By Maurício Szabo, ago

A new Chlorine is almost done!

For the last few months, I’ve been working on a new version of Chlorine (now that Pulsar is on a good track). Here I want to share what to expect of this new version.

For a quick TL;DR; it’ll have better ClojureScript (shadow-cljs) support, fix some bugs related to evaluating code and the REPL being “locked” without returning the results or evaluating new commands, and have better configurable parameters. Things will probably break a little bit – it’s not a non-breaking-change, unfortunately – but hopefully it’s good enough that people will want to migrate to the new version.
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By Maurício Szabo, ago