Day 9/90: Enums and Option type

90 Day Rust Challenge: Zero to Production

Today I wanted enums and option type to feel like a real engineering decision, not a syntax demo. The useful shift was making enums and option type feel like clear values, control flow, and data shapes instead of syntax trivia.

The checks that mattered were clear value shapes, control flow that makes valid states obvious, and small functions with one reason to change.

The failure mode I was actively trying to avoid was using broad or vague types until the data model stops explaining itself. I wanted enums and option type to feel like something I could explain at a whiteboard or in a code review, not just something I recognized from docs.

That is the bar I want from this track: code that stays readable when requirements move, not just code that compiles today. I also want to keep tracing one concrete path through the code because that exposes weak assumptions faster than a larger demo.