Strongly Typed Units

content/posts/strongly-typed-units.md

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+---
+title: "Using Rust's Type System to Verify Your Maths"
+date: "2021-02-02T16:27:17+08:00"
+draft: true
+tags:
+- Rust
+- Architecture
+---
+
+Audience: Software engineers wanting to use Rust in the real world.
+
+Introduction:
+
+- One of the most powerful tools in my CAD/CAM toolbelt
+- How can I write code with less logic errors or stupid bugs?
+- Use the Mars Lunar Orbiter as an example
+
+Motivation:
+
+- Code involving maths is often hard to read
+- Primitive obsessions/stringly-typed APIs
+- Often comes up in physics
+  - CAM and simulation
+- Improves readability and makes code self-documenting
+
+The `CanvasSpace`/`DrawingSpace` dichotomy in CAD:
+
+- Mention experience with `arcs`
+- Using a common `Vector2D` type can lead to confusion
+- The only link between the two is the `Viewport` and its transformation matrix
+
+War Stories:
+
+- Angles and modular arithmetic in Profiler 9
+  - Is that `double` in radians or degrees?
+  - Soooo many bugs where an arc would be around the wrong way. For example,
+    instead of having a nice rounded corner it might be inverted or rotated by
+    90 degrees
+  - Would split it into `Angle` (`0 <= Angle < 2π`) and `AngularDifference`
+    (`-2π <= Angle <= 2π`) to represent the different domains and operations
+
+Conclusion:
+
+- Use the type system where you can!
+- Crates like `euclid` and `uom` are amazing
+
+{{% notice note %}}
+The code written in this article is available [on GitHub][repo]. Feel free to
+browse through and steal code or inspiration.
+
+If you found this useful or spotted a bug, let me know on the blog's
+[issue tracker][issue]!
+
+[repo]: https://github.com/Michael-F-Bryan/💩🔥🦀
+[issue]: https://github.com/Michael-F-Bryan/adventures.michaelfbryan.com/issues
+{{% /notice %}}
+
+