Table of Contents

These are some notes on my opinions on Rust after one year of using it.

Thoughts and remarks Link to heading

These pros and cons are mostly relative to C++, the language I used for the past ~10 years.

Good Link to heading

  • Sum types!
    • Option and enum are so much nicer than optional and in particular variant.
  • Build system
    • Never used 3rd party code/libs in personal C++ projects.
    • Use random crates all the time now!
  • Rust Analyzer
    • C++ had YouCompleteMe in Vim, but Rust Analyzer worked out of the box and coding is so much nicer now.
  • No more need for !=nullptr
    • If you want to use an optional, you are forced to check it’s existence.
    • with if let Some(value) = optional, you can do the check and unpacking in one go, saving bugs.
  • C++ move semantics are an afterthought – don’t forget to move() when needed! In Rust, this comes naturally.
  • Lifetimes save bugs. It’s tedious, but as long as you’re doing nothing crazy you just keep applying suggestions until it works.
  • Turn your linux app into a webapp in 1 simple step!
  • I don’t actually believe Rust is hard to learn. Maybe if you’re used to C, but coming from C++11, Rust simply better corresponds to my mental model of code than C++ does. Sure it takes time, but what is the last time you learned a new language? After 1 year, I think I know/understand a larger percentage of Rust than I knew C++ after 10 years.
  • This is the right time to start! Lots of new cool features recently!
    • let-chaing: if let Some(val) = val && val > 0 { .. }
    • let-else: let Some(val) = val else { return; };
    • GATs
  • ranges done right. (Well, at least more sane than C++-20/23 ranges)
  • Traits: tell the compiler that every type with .begin() and .end() is indeed a container.
  • No header/implementation split, and no header mess. Sane modules that map to directories!
  • Single source for all documentation!
  • WASM: taking your SDL2 based rendering and porting it to HTML Canvas in a day is very satisfying!
  • Expressions everywhere!
    • let x = if var {1} else {0};,
    • let x = { let a = 1; a };,
    • let x = loop { break 10; };.
  • Simple and consistent struct initialization: let x = X { a: 1, b: 2 };

Bad Link to heading

  • No equivalent of template-templates.
  • Using global/static convenience variables in simple programs is pain.
  • yes, fighting the borrow checker can be annoying, especially if you don’t know what you’re doing. Just remember: don’t try to make a struct that contains references into itself.
  • Using generic types has some rough edges
  • Haven’t used it yet for standalone files. In competitive programming/Project Euler, it’s too much overhead to create a new project for each problem.
  • Casting between usize, u32, and i32 all the time when using graphics libraries gets boring fast.

My programming language journey Link to heading

Lego mindstorms Link to heading

  • Age 11-13

LabVIEW Link to heading

  • Age 13-15

C++ Link to heading

  • Age 15-26
  • Oh my god, it’s so nice to just type what you want instead of dragging/dropping boxes and wires
  • Started at C++11, solving Project Euler problems mostly
  • Only learned about references after a few years of using C++.
  • Never really used pointers in my own projects.
  • I couldn’t tell you how to declare and initialize a native array.
  • Also, I still can’t write new
  • Big fanboy; watched ~half the CppCon videos after each edition.
  • Always excited for the next edition.

Python Link to heading

  • Age 21-
  • BAPCtools, a 5kloc python project

Rust Link to heading

  • Age 26-
  • Started summer 2021 with a small hobby project
  • Now used in AstarPA, a 14kloc pairwise alignment project
  • Read all the blogs on r/rust.