• Day Summary

  • Context

• Reading

• Coding Practice

• Reflection

• Key Learning

• Total Time Spent

Day Summary

Last night was a full 8 hours. I still woke up feeling like I hadn’t fully caught up (makes sense after three rough nights — one good night doesn’t erase sleep debt).

Busy day: job work, moving between apartments, a tiny workout. I did my Daily Quest late, but I did it. I reached the Collections chapter and talked through vectors vs arrays and String vs &str. I keep getting hung up on the idea that string slices are basically just “peeking” into data I already own, and why that behavior isn’t simply part of String. Substrings aren’t conceptually hard; it’s all bytes in sequence.

I’m basically using AI as a Socratic partner — asking the whys, hows, and whens — and I keep harping on not using insider terms; I want plain concepts tied to what I already know. For standard-library items I can jump to references in Neovim; for built-ins, “go to reference” doesn’t really help.

Net: win logged. I handled admin, job work, moving, ate properly, squeezed in a short workout, and still put in the Daily Quest at the end. A little proud of that.

• Daily Quest: 60 minutes (completed; late).
• Reading (60m, +6 pages): p.194 → p.200 — started Collections.
• Coding: none.

Context

• Late-evening session; energy low but got it done.

Reading

• Vectors vs arrays: arrays = fixed size (often stack), Vec<T> = growable (heap). Clear use-case split: known, fixed data vs runtime-sourced, variable data.
• Strings: String presented as a growable owner (wrapper over Vec<u8>).
• Slices: friction point — needing a separate type (&str) just to view/substring data you already “own.”

Coding Practice

• None today.

Reflection

• The String vs &str split still feels ergonomically off: “I own the car but need a neighbor’s bike to drive it.”
• Zero-allocation is nice in theory, but the extra type to remember/use feels like overhead without obvious benefit during learning.
• Despite the ranty mood, progress happened; kept moving through the chapter.

Key Learning

• Arrays ↔ Vec<T> distinction makes sense for fixed vs growable data.
• String is an owner; &str is a view (borrowed slice) into UTF-8 data. The language forces you to be explicit about viewing vs owning.
• Practically: you can take a slice from a String (e.g., &s[..]) without copying; it’s just a different type at the call site.

Total Time Spent

• Reading: 60m
• Coding: 0m
• Daily total: 60m

PCT (Project Cumulative Time): 23h29m