Choose the Right Option

Logan Smith explains the memory layout and API design trade-offs between Option<&T> and &Option<T> in Rust.

"Reference-to-Option" and "Optional-reference"* are both ways to represent "a reference to a value that may or may not be there" in Rust. So which one should you use in your APIs? Hear me spoil my answer within the first 10 seconds, and then stick around to get real nerdy about a topic you may have never spent 15+ minutes thinking about before. Featuring special guest appearances from memory layout visualizations (feat. niche optimizations), the venerable ToOwned trait, and me saying the word "Data" several hundred times. And yes, I do in fact regret missing the opportunity to make a Sum 41 reference during the memory layout visualization. Option docs - doc.rust-lang.org/std/option/enum.Option.html ToOwned docs - doc.rust-lang.org/std/borrow/trait.ToOwned.html Niche optimization / "null pointer optimization" (which IS guaranteed for Option-ref-T) - doc.rust-lang.org/std/option/index.html#representation I use the amazing Manim library for animating these videos, and I edit them with Blender and Audacity. manim.community/ blender.org/ audacityteam.org/ *YouTube doesn't allow angle brackets in video descriptions.