Why const Doesn't Make C Code Faster

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Translations:中文, русский

In a post a few months back I said it’s a popular myth that const is helpful for enabling compiler optimisations in C and C++. I figured I should explain that one, especially because I used to believe it was obviously true, myself. I’ll start off with some theory and artificial examples, then I’ll do some experiments and benchmarks on a real codebase: Sqlite.

D as a C Replacement

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Sircmpwn (the main developer behind the Sway Wayland compositor) recently wrote a blog post about how he thinks Rust is not a good C replacement. I don’t know if he’d like the D programming language either, but it’s become a C replacement for me.

D in the Browser with Emscripten, LDC and bindbc-sdl (translation)

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Here’s a tutorial about using Emscripten to run D code in a normal web browser. It’s uses a different approach from the Dscripten game demo and the dscripten-tools toolchain that’s based on it.

LDC has recently gained support for compiling directly to WebAssembly, but (unlike the Emscripten approach) that doesn’t automatically get you libraries.

You can find the complete working code on Github. ./run.sh starts a shell in a Docker image that contains the development environment. dub build --build=release generates the HTML and JavaScript assets and puts them into the dist/ directory.

This tutorial is translated from a Japanese post by outlandkarasu, who deserves all the credit for figuring this stuff out.

Unfortunately, Garbage Collection isn't Enough

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Here’s a little story of some mysterious server failures I had to debug a year ago. The servers would run okay for a while, then eventually start crashing. After that, trying to run practically anything on the machines failed with “No space left on device” errors, but the filesystem only reported a few gigabytes of files on the ~20GB disks.

How Inheritance and Polymorphism Work

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I’ve promised to write a blog post about the DIY polymorphic classes implementation in Xanthe, the experimental game I once wrote for bare-metal X86. But first, I decided to write a precursor post that explains how polymorphism and inheritance work in the first place.

Making a Compile-time Brainfuck Compiler in D (translation)

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NB: This post is just a translation (with some extra comments by me). Credit goes to the original and the C code generator that inspired it.

Code Jam 2016 Qualification Round

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This year’s qualification problems were all straightforward puzzles. None of them needed sophisticated implementation techniques, or advanced algorithms, or complex data structures. They just needed patient analysis and careful coding. That’s nice from one perspective, but unfortunately it’s hard to make a good comparison of programming languages when every problem can be solved with just loops and arrays. Still, I succeeded in my goal of producing every output with a different (sometimes terrible) language.

Here’s my code and commentary on the problems. Warning: spoilers ahead. If you haven’t looked at the problems yet, go do that first.

How Dirtying Pure Functions a Little Can Be Useful

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Functional purity is a valuable concept for writing maintainable code, though outside of functional programming languages like Haskell, it’s often treated like a nice-but-expensive luxury. But it turns out that pure functions that aren’t quite so pure can be cheap while still having concrete benefits for code in non-functional languages like C++, Java and Python. For D code, this is supported by the language itself, but there’s nothing D-specific about the overall idea.