Guillaume Chereau, Software Engineer

The Abel-Ruffini theorem states that there is no solution to the general polynomial equation of degree five (quintic equation) that can be expressed with the common operations: (+, -, x, %), plus √ (radical of any degree). In this post I’ll try to give my quick understanding of the proof, without explicitly relying on group theory or Riemann surface. As usual on this blog, this is all hand wavy. For a proper introduction to the proof I recommend the excellent book “Abel’s Theorem in Problems and Solutions” by V....

In this post I am going to present a few of my favorite command line tools that might be of interest to programmers who prefer to work directly from the terminal. (Note: since I didn’t want to put screenshots or html, I removed the colors from the examples. Most of those tools actually make use of ANSI escaping to colorize their outputs) ag – The Silver Searcher $ ag LookAdjust src/g_game....

Let say you want to add some script support to a C program, like lua or maybe even something simpler where all you can do is call a function with some given arguments: #include <stdio.h> void my_func(int x, const char *s) { printf("my_func called with x=%d, s=%s\n", x, s); } int main() { // Will call my_func with 2 and "hello". script_call("my_func", 2, 'hello'"); } Since C does not support reflection, there is no way to implement the script_call function without some extra work....

There is spectrum on how easy it is to integrate a C (or C++ for that matter) library into a project. The issue is that the C ecosystem does not have a standard dependency manager, so each project big enough to require the use of external libraries needs to find a way to integrate them, and it is usually a significant source of problem just to get them to compile. Note that I am not even talking about how to use them....

The Newcomb paradox is stated as a fictional situation where a player enters a room with two opaque boxes, A and B. A always contains a small amount of money (let say $100), and B contains either nothing, either a larger amount of money (let say $110) 1. The player gets to pick one or both boxes and leave the room with them. The catch is that before the player enters the room, an ‘all knowing’ entity prepared the boxes and filled the box B with money only if it predicted that the player will not pick the A box....

The next version of the C standard (C23) brings two new features that I am not enthusiastic about. One of them is the nullptr constant, the other one is the “new” auto keyword1. I will try to explain why I don’t like it. The new proposed auto keyword will work basically like in C++. You will for example be able to write: auto x = 10; auto ret = function(); Instead of:...

The blue eyes island is a tricky logic puzzle that has several variations. The one I was first told was: A group of people live in an island with no contact with the outside world. Eyes color is big taboo for them and they strictly follow this rule: if anybody figures out the color of their own eyes, they will commit suicide the following night. Everybody knows the eyes color of all the other islanders, but nobody knows their own eyes color....

This post will be my attempt to explain intuitively what is Quantum Field Theory. This idea came to me after reading two books: “QED: The Strange Theory of Light and Matter” by Richard Feynman, and “Quantum Field Theory in a Nutshell”, by A. Zee (that I only started). Both books use path integrals, but in a very different way: Feynman tells us that the particles can move anywhere they want in space and time, while Zee uses conventional ‘forward in time only’ paths but of a ‘mattress’ and not just one particle....

As of 2019, C and C++ are the only programming languages that are supported by virtually any platforms on the market. For example both iOS and android support compiling C and C++ directly as part of their official IDEs. This is one of the reason why I decided to write my voxel editor Goxel in C99: I wanted to be able to run it on Linux, Mac, Windows, iOS, and now I am working on a Android port as well....

I recently started to see how to integrate a generic script language into my voxel editor Goxel. I want to use something light and easily embeddable into a C application. One obvious choice for this is to use Lua, but I also wanted to try Duktape, a lightweight JavaScript interpreter. In this post I’ll give some of my conclusions after trying both. 1. SIMPLICITY TO EMBED Both Lua and Duktape are relatively easy to embed into a C application....