Posts Archive on Lucas E M M. comments

My gpg key

Tue, 28 Jul 2026 09:35:00 -0300

Erlang small QoL

Sun, 15 Mar 2026 12:58:00 -0300

This is small proposal to improve erlang navigation when coding. It is a two piece adjustment:

In the Makefile

tags:
 find src include deps -name "*.[he]rl" -print | xargs etags -o TAGS

And in emacs, you can do this:

(defun le2m/erlang-update-tags ()
 (interactive)
 (let ((root (locate-dominating-file default-directory "Makefile")))
 (when root
 (let ((default-directory root))
 (shell-command "gmake tags")
 (message "Tags updated")))))

(advice-add 'erlang-compile :before #'le2m/erlang-update-tags)

When typing C-c C-k, the TAGS file will be “automagically” created

Org-roam over org-brain?

Sun, 01 Mar 2026 21:39:00 -0300

Org roam seems to be very nice indeed. Maybe I will ditch org-brain…

Tmux over fancy terminals

Wed, 14 Jan 2026 19:15:00 -0300

I do like minimal stuff so I have avoided most of the terminal with tabs and fancy “features”. Turns out, all I want, I can get from tmux.

A few tips from my usage

divide usage of session per context: new-session
inside same context, use windows: new-window or prefix+c
Use list-window (prefix+w) or list-session (prefix+s) to navigate

If you are a dwm user, I have just set up to open the tmux directly

Reviews

Thu, 06 Nov 2025 18:47:00 -0300

Some things that I enjoy

TV shows

Breaking Bad
Better call Saul
Mr. Robot

Boardgames

Oath is really interesting <2025-11-06 Thu>

My wife kindly gave me this new boadgame called Oath. It is a game in which the outcome of one game affect the next ones. Similar like a perpetual non-ending campaign.

The other side of it, it is designed to create kingmaking. Usually, I don’t like kingmaking but here it works. Maybe because it was designed around that? One could argue that Root (by the same designer) also has kingmaking, but in Root the scoring seems a bit more arbitrary on who is going to win.

Emacs mode line

Fri, 26 Sep 2025 11:20:00 -0300

If like me, you don’t mind how pretty the modeline looks in your emacs, then you can set it pretty easy.

Why would you want to do this? Well, what happens is that I have a pretty small screen in my monitor and if I split vertically, I lose some useful information like the time on a task.

Now to the how:

(setq-default mode-line-format
 (list "%e"
 mode-line-remote
 mode-line-modified
 mode-line-front-space
 mode-line-frame-identification

 mode-line-buffer-identification " "

 mode-line-position project-mode-line

 " "
 mode-line-misc-info
 mode-line-end-spaces))

Not sure what all that is? Checking the docs in emacs is ez ;]

Org mode audience

Wed, 20 Aug 2025 08:58:00 -0300

Org-mode is not for everybody, I think. However, I do think that org-mode is for anybody that is willing to learn enough elisp to shape the desired workflow.

A keyboard utility for everyone

Mon, 18 Aug 2025 14:01:00 -0300

Have you ever noticed that your on your keyboard the letters j and f both have a little dent on it. Well, that is not by chance. I will tell you more, my brazilian keyboard as well as my american keyboard, also have it.

Why? It is a way for you to find the “rest” position of your hands without you having to look at it. Is your mind blown? Mine was!

Improving mode line in emacs

Fri, 08 Aug 2025 11:06:00 -0300

A nice UI feature in emacs in my configuration was having a bit more control over the mode line (the thing between the buffer and the mini buffer).

Now that I have been controling my hours with emacs org clock, it is really nice to have at glance how many hours I have been working. The issue is that sometimes, my config has a bunch of minor modes and the mode line has a lot of noise. dminish-mode was a great finding for this!

Improved (maybe) indenting on save

Fri, 30 May 2025 11:30:00 -0300

I realized that sometimes identing the whole buffer might not be the desired output. That because if the file is on different identation, your git commit might be hard to follow.

Because of that I studied a bit emacs lisp and came up with similar idea. On save, indent only the function that you are working on.

(defun le2m/indent-function ()
"indent only function"
;; (interactive)
(delete-trailing-whitespace)
(let ((begin (save-excursion (beginning-of-defun) (point)))
 (end (save-excursion (end-of-defun) (point))))
 (indent-region begin end nil)))

Indent file on save, please

Thu, 08 May 2025 08:32:00 -0300

So, I discovered that I really like to format the code on save (I am not the best typer). So emacs to the rescue:

(defun le2m/indent-buffer ()
 "indent whole buffer"
 (delete-trailing-whitespace)
 (indent-region (point-min) (point-max) nil)
 (untabify (point-min) (point-max)))

(add-hook 'clojure-mode-hook
 (lambda ()
 (add-hook 'before-save-hook
 #'le2m/indent-buffer
 t t)))

I did this on clojure-mode but it can be done in any mode I guess.

Wait, do you want to choose a alias with cider?

Sat, 03 May 2025 10:31:00 -0300

Another thing you may want/need is to use an alias when connecting cider. I know that cider can have that set up on your configuration. You can use .dir-locals.el to set up per project but I personally prefer to be able to choose when connecting.

(defun start-cider-repl-with-lein-profile ()
 (interactive)
 (letrec ((profile (read-string "Enter profile name: "))
 (lein-params (concat "with-profile +" profile " repl :headless :host localhost")))
 (message "lein-params set to: %s" lein-params)
 (set-variable 'cider-lein-parameters lein-params)
 (cider-jack-in '())))

 (defun start-cider-repl-with-cli-profile ()
 (interactive)
 (letrec ((profile (read-string "Enter profile name: "))
 (cli-params (concat "-A:" profile)))
 (message "cli-params set to: %s" cli-params)
 (set-variable 'cider-clojure-cli-aliases cli-params)
 (cider-jack-in '())))

Running repl commands in cider (emacs)

Wed, 23 Apr 2025 19:46:00 -0300

Ok, I will admit.. this took a while. But I have found a nice way of doing this.

What is this? Well, let’s say that you have a command to start your server in user namespace. With this cool feature, now you can run this with a emacs command (or shortcut if you bind it).

The cool thing about this is that the command will run with the namespace from the repl and not the last ns that you loaded with cider =].

Need dwm class? xprop

Sun, 13 Apr 2025 21:32:00 -0300

Need some info for dwm? Maybe for the rule section? Use xprop and find WM_CLASS

New fun hobby

Fri, 11 Apr 2025 23:18:00 -0300

Why not have another hobby? =p

Figure 1: jaylib basic window

New host

Mon, 18 Nov 2024 15:07:00 -0300

New host, new css

Restclient is dead… Now we have verb!

Wed, 16 Oct 2024 15:26:00 -0300

Recently I found an interesting mode in emacs to manage and run http requests!

enjoy! heheh

Go croqui added to my projects!

Thu, 10 Oct 2024 09:47:00 -0300

Just remembered that I had a simple project in golang =] https://git.sr.ht/~lucasemmoreira/go-croqui

Emacs code navigation? TAAAGS!

Mon, 08 Apr 2024 16:52:00 -0300

Do you know when you open a code file and you want to navigate it but you have to fire up a whole enviroment just to do it? In clojure, would be cider, in python it would be elpy and so on…

Well, get ready feel free! All you need is a command line and vanilla emacs!!

The command is etags. What this command does is look for all the definitions you made in the files you pass as an argument with the language and it will create a TAGS file in the current directory.

My first clojure project on the list!

Mon, 01 Apr 2024 22:37:00 -0300

Recently, I created a new page on this website. I decided to put all cool projects that I made/find around the web (spoiler alert, for now it has only my projects hehe).

I have already put a few, but I noticed that none of them are in clojure which is my most fluent programming language these days.

So, let me introduce you to: invoice-translator!

The idea of the project is for you to be a little bit more aware of how you are spending your money every month. You can use something like gnucash for something like this, right? Well, yes but the tricky part is that you would have to populate the data. Or translate it to gnu-cash if you will.

Integration test in a good way

Wed, 24 Jan 2024 13:40:00 -0300

This is another tale of redemption… I really enjoy minimalistic solutions and yet, I was not using for integration tests…

So, as everything that needs a start, what was the problem? For some time, I have been thinking about integration tests. What I am calling integration here means a way to test an API that goes through other APIs.

The non minimal

I tried a few approaches. One was to create a “fake” data structure that would represent the return of one API but that proved to be very difficult to insert in my coding routine.

Cool projects

Thu, 18 Jan 2024 11:04:00 -0300

Mine

Here I will list some of my cool personal projects.

lets-meet small script that helps you start a meeting on OpenBSD
bmark a way to manage your bookmarks with a sanity check
pdfminer jar to transform pdf into string
hitter simple tui to check if website is up
pomodoro a shell script to run your pomodoro and save your tasks
invoice-translator a clojure project that transform your pdf invoice into data.
go-croqui helper software to generate random tables in excel

Emacs? No, emacsclient!

Tue, 16 Jan 2024 21:01:00 -0300

This is a shoutout for all of you who are tired of waiting emacs to load on startup or annoyed to feel forced to leave an instance open.

emacsclient can save you from that. All you have to do is to leave an daemon open. Don’t use (server-start) because that will force you to have an GUI or terminal open at all time. The solution? A command.

On your terminal (or .xsession file):

Finally, a whatsapp tui!

Thu, 04 Jan 2024 11:49:00 -0300

Ok, finally I have found a (half) solution to the whatsapp web problem. The problem being the “web” part of it… I don’t like having the browser open just to text chat. So for some time I have been looking for a text user interface solution to this.

In other words, a less RAM intensive little piece of software. The important key part for this solution is matterbridge. It is a piece of software that connects two chat enviroments that you have.

Erlang? Erlang!

Sat, 09 Dec 2023 20:18:00 -0300

Let’s dive into some new language programming. Functional of course… Erlang!

In Openbsd, did some tweaks into the installation process…

~> doas pkg_add erlang rebar
~> ln -s /usr/local/bin/erl<version> ~/bin/erl # my personal bin directory
~> ln -s /usr/local/bin/rebar<version> ~/bin/rebar

It was not so obvious for me but it seems that rebar is to erlang like leiningen is to clojure. And as such, you can initialize your project quite easily

rebar new umbrella prj-name

Also your first time?

A bit more on rebar

You can see all templates and understand them better with

tmux colors

Thu, 07 Dec 2023 19:44:00 -0300

I am starting to explore tmux and emacsclient -t. But it is annoying that emacs gui and in the tmux terminal was being colored differently. The solution?

set -g default-terminal "tmux-256color"

NEOmutt with html glasses

Tue, 05 Dec 2023 10:17:00 -0300

In this post I created a macro to open those annoying html e-mails with your favorite browser. Well, with neomutt I did not manage it to make it work so I went on a different approach. Arguably, a more elegant.

So, (neo)mutt has the mailcap file which is a file that tells (neo)mutt how to open a file tipe from it.

So if I write in the mailcap file this:

text/html; w3m -v -F -T text/html -dump %s; copiousoutput

it tells (neo)mutt that any text/html file should be opened with w3m with these arguments and copiousoutput will tell to open in the internal pager (this can set to be an external pager, however my default is internal).

neomutt <3 notmuch

Sat, 02 Dec 2023 08:48:00 -0300

This is a tale of stubbornness. I’ve heard about notmuch, quite sometimes and yet, I did not use it. I was bit confused reading the docs but then I read this:

Notmuch does not modify or delete your mails. This is one of the main design principles of Notmuch.

That gave me some nerves to try this on! And it is worth it!

To put it simply, notmuch is a indexer of all your emails and make search annoyingly easy. Once you go with the basics

Zoom vs OpenBSD

Sun, 08 Oct 2023 11:46:00 -0300

I do not mind saying it again, OpenBSD is pretty cool, however it does has its quirks. Recently, I had a fairly important meeting in Zoom in which I would make an presentation and I did not make it because I could not enter the room. All it appeared to me was and enternal “Joining” and the endless MS circle spinning.

So, let’s fix it shall we?

Apparently, in order to make Zoom work, one must have wasm enabled in your system. By the way, this is what I would call a bloated piece of software… it only is a videoconference software… geez…

Data science with clojure

Wed, 16 Aug 2023 18:27:00 -0300

Hypothetical reader, you must be asking yourself:

“Why not use python? There are a gazillion libraries and methods already prepared to go! So… why?”

I will tell you one reason in this post! One small disclaimer though, I will not discuss performance here, only convenience ;]

Actually, the point I will make is theoretically valid for any lisp dialect. But I have found a pretty nice project with a solid library in clojure, so here we go.

Buy me a coffee!

Tue, 15 Aug 2023 12:50:00 -0300

Pix (BRL)

41ad8aaa-792c-4ae6-a45e-dc35607b1aea

Monero

83d6gFo4P3kRPAQbkNsUiyVXF6SgLutGQ1kH4DXdWPYT7hzSSSGkDPNfQmTx6gijjcBRqwAfzzNz4VrcMbNjgYQ5Ao1DhP8

Resume

Mon, 14 Aug 2023 22:07:00 -0300

Who am I?

I graduated in applied mathematics into computer science with emphasis in optimization. While studying optimization, I spent most of the time with operational research and mixed integer optimization. I really like functional programming and try my best follow its best practices.

Skills

Operational system

I use regularly a macbook.
I use regularly OpenBSD.
I used for quite some time Arch Linux.
I have some experience with Ubuntu.

Programming languages

I use clojure every day.
I feel comfortable coding in python.
I have toyed with (and enjoyed) golang.

Math

I have studied in depth linear and integer optimization.
I feel comfortable working with non linear optimization problems.
I have some experience with data science projects. Mostly with classification problems.
I have some knowledge in statistic.

Hardware

I like to disassamble computers to fix or change components, but I don’t do it very often.

Working Experience

Dataico

2024-05 - now

Fix incanters core.view in dwm

Sun, 11 Jun 2023 13:34:00 -0300

Now, let’s face it. dwm is awesome. But sometimes, it needs adjustments. If you are using incanter and cannot see a plot with core.view function in a cider enviroment, all you have to do is export this variable into your enviroment before firing up cider.

export _JAVA_AWT_WM_NONREPARENTING=1

Uploading in firefox vs OpenBSD

Wed, 07 Jun 2023 16:20:00 -0300

I had some issues adapting to some security features in OpenBSD, for example, to have videoconferences (let’s meet). Another interesting problem I had was that I could not upload files from firefox.

To fix that, all I had to do was enter on this “page”: about:config and change this setting to the specified path that I wanted dom.input.fallbackUploadDir.

There you go, now you can upload files from this directory on your firefox.

Mutt's glasses for html email

Mon, 29 May 2023 12:19:00 -0300

Mutt is awesome but html email not so much… well, let me give you a possible solution: create a hotkey (F) to open html email in your favorite browser.

macro attach F \
 "\
 <enter-command>unset wait_key<enter>\
 <shell-escape>rm -f /tmp/mutt-attach<enter>\
 <save-entry><kill-line>/tmp/mutt-attach<enter>\
 <shell-escape>$BROWSER /tmp/mutt-attach &<enter>\
 "

Bookmark unix-style!

Thu, 11 May 2023 19:23:00 -0300

Hypothetical user, do you use any bookmark system? What? Only on firefox? Why am I calling it “system”?

Well, you don’t need to use bookmark only for webpages and restricted to the browser. A little bit of rofi and shell script, and there you go: bmark!

pomodoro is now its own thing!

Tue, 09 May 2023 19:00:00 -0300

I started using my pomodoro script again, and made few improvements. Also, I separated in its own repository.

Let the charge come back, thinkpad…

Tue, 25 Apr 2023 22:10:00 -0300

So, I have a thinkpad x270 which is pretty good. However, for the past few months, I was having a lot of trouble to charge it. There was a single position and mood for it work charge normally.

Well, no more! Let’s face the challenge of fixing it by myself. First things first, diagnosis:

Since the computer was charging, there was a specific position to work and, probably most important, the charger was loose when connected… There you go, probably there is a problem with the dc jack. Let’s get a new one.

Extract infos from a pdf!

Thu, 23 Feb 2023 10:58:00 -0300

Hypothetical reader, I bet you always wanted to extract the text from a pdf file. Sure there are a few big tech options but let me appeal to your minimalistic side: pdfminer! This is a simple jar that extracts the text from the pdf into a huge string.

What is this good for you might ask. Well, you can extract the code payment from an invoice. How? There you go: invoice =]

Meetings in openbsd

Tue, 21 Feb 2023 13:15:00 -0300

Ok… I have been using a little bit more OpenBSD, and I was having some issues to use it during calls. After some research and experimentation, I have thought a way to make it happen! So it was born lets-meet!

It is simply a toggle to enable/disable microphone and camera. Enjoy!

Searching for packages in openbsd

Thu, 05 Jan 2023 10:58:00 -0300

Finally! I am using openbsd! It is quite interesting but somethings are different. I will need to post somethings to help me remember =]

Starting by package search:

pkg_info -aPqQ package | sort

where package is what you are looking for. Thanks for the tip Umgeher!

All praise stash

Mon, 07 Nov 2022 10:57:00 -0300

Today I figured a pretty cool git command. Up to this day, sometimes I get a bit disorganized with the branches, and git stash came to save the day (or at least some working stamina).

Here is the procedure:

“Oh no! I forgot to change the branch before making changes”

git stash save "name of the mistake"

Now, moving to the correct branch

git checkout the-correct-branch

Recover the modifications

git stash pop

And, a nice command:

Remap your keyboard!

Sat, 05 Nov 2022 11:08:00 -0300

Why? Well, because as an emacs user, you are probably tired of your pinky trip to ctrl in order to do the “chords”.

I would assume, hypothetical reader, that you have already tried changing caps for ctrl. Well that’s nice, however, let me introduce you the better idea (giving credit where is due, thanks for this Umgeher!).

It is a lot more comfortable and an easier transition to change shift->ctrl and caps->shift. The muscle memory for shift stays the same and ctrl is in a much more comfortable position. Here is xmodmap script to arrange that:

Patching your way to contribution!

Wed, 26 Oct 2022 11:39:00 -0300

Hypothetical reader, I know what you are thinking. You have some interesting projects, but I am not sure to engage on those because on source hut there is no way to make a pull request (at least, I have never found to the day of this writing).

Well, this make a nice oportunity to learn about patch in git! So, the magical command I use

git format-patch -x

where x is the number of commits that I did or

Managing dependencies in clojure

Mon, 03 Oct 2022 13:04:00 -0300

Today I was having a hard time to load a nice lib for managing excel files (https://github.com/mjul/docjure). I was having some weird problems at loading them in cider (btw, if you don’t use it, start now!).

I gave some search into it, and lein has a nice feature to handle dependencies. The command that saved me this time was:

lein deps :tree

It gave me a quick report on what was strange with the dependencies. Some examples:

Going Hugo for framework!

Mon, 13 Jun 2022 09:06:00 -0300

So, the time has come! I also started using Hugo for my blog framework. Previously, I was using org-static-blog for my framework and honestly I was pretty happy about it.

But things changed when I wanted to make a second website. org-static-blog is pretty neat to work inside emacs, however to use on a second project there is a lot of setup to do. Facing that problem and knowing about Hugo and ox-hugo, it was a no brainer.

Divide and Conquer to optimality!

Thu, 17 Mar 2022 17:12:00 -0300

This week I made a pretty cool achievement for the paper on the wall that says that I am an applied mathematician. This week, I developed a branch and bound to solve a mixed integer linear problem.

Yeah… so?

Well, hipothetical reader, if you asked me that, I would say that you are not familiar with the power of integer programming. This kind of technique is pretty useful in the industry, in an area called operational research.

A first (not bad) emacs experience

Fri, 04 Mar 2022 14:42:00 -0300

Well, not for me. I have been using emacs for almost a decade now and I have used bad configs and good ones. In the past few years that I am feeling more comfortable with lisp, I have been enjoying to tweak the configuration more and more.

My girlfriend has recently come to the good side of workplace and could drop Windows and its tools. In this new world, she tried to go into the Linux and emacs was something that I was more than eager to show her!

Artix vs NVIDIA

Mon, 14 Feb 2022 00:00:00 -0300

What happened?

Today, when I turned my computer on to log in, X complained that could not connect…

Why did that happen?

On friday, I tried to solve a glitching issue on brave, and I found online that someone solved by changing some settings on the nvidia. This genius that speaks to you, hypothetical reader, tried to download nvidia-settings to find out that the solution was elsewhere. All I had to do was to disable hardware accelaration on brave://settings/system.

You don't need browser to check if a website is up!

Mon, 07 Feb 2022 11:12:00 -0300

Well, the title is quite an obvious statement… You can use softwares such as restclient from emacs, curl and probably a gazillion others.

However, there is not another one made in janet, authored by me, made in the last month! I can guarantee it!

The Goal

Well, my goal here was to make a simple software that did one thing and well. That one thing is to check multiple urls if they are up and the status they would return.

Pomodoro with shell script

Wed, 02 Feb 2022 19:13:00 -0300

By now, you must be asking yourself: “Oh my god, all you know is janet/functional programming?!”, to which my answer would be a resounding “Yes!”.

However, today I decided to step a little bit outside my comfort zone and make a little script to help me use pomodoro for productivity.

Like you, hypothetical reader, I use dwm with dmenu. With these you can easily create a pomodoro executable to work for you. I say easily because I have no experience with shell script and I made it happen.

Web view in mutt

Thu, 27 Jan 2022 08:02:00 -0300

I know for a fact that you, hypothetical reader, are a mutt user. And as such, you know how frustrating html emails can be. Recently I was having this particular problem to see Jira emails.

Behold the solution!

In the mailcap file:

text/html; w3m -v -F -T text/html -dump %s; copiousoutput

Moving averages beatifully

Thu, 20 Jan 2022 11:10:00 -0300

So this is another post on the janet journey. My goal here was to create a simple moving average function in janet (maybe just as a functional programming lover).

The code

I created a repo named numja that I intend to put all mathy stuff there. And moving average fits that category.

The second step was to create a small script that would run with the new “lib”.

The result

Simple as the proposition is, simple the code and simple the result. I used the “lib”, and plotted with gnuplot and voila!

New year, new goals, more posting!

Wed, 12 Jan 2022 00:00:00 -0300

A new year has come and hopefully it won’t be 2020 too again (although it is).

My plan is to post more often from now on, hence the monero qr code =]

Janet? Janet!

Thu, 21 Oct 2021 00:01:00 -0300

Do you like C but changed because you were tired of the low productivity, the annoying syntax and - oh my god! - Segmentation fault? Holy shit! Me too!

But then, a couple of years ago, a friend of mine showed me Janet. And I was from the get go hooked! It took me a while to create something in it, now I have something to show.

Why Janet?

Come on… google it…

Hello world (again)

Sat, 16 Oct 2021 00:01:00 -0300

A new try with a different css…

Monero

Mon, 01 Jan 0001 00:00:00 +0000

83d6gFo4P3kRPAQbkNsUiyVXF6SgLutGQ1kH4DXdWPYT7hzSSSGkDPNfQmTx6gijjcBRqwAfzzNz4VrcMbNjgYQ5Ao1DhP8