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SKILL.md
npx skills add actionbook/rust-skills --skill m14-mental-model
Use when learning Rust concepts. Keywords: mental model, how to think about ownership, understanding borrow checker, visualizing memory layout, analogy, misconception, explaining ownership, why does Rust, help me understand, confused about, learning Rust, explain like I'm, ELI5, intuition for, coming from Java, coming from Python, 心智模型, 如何理解所有权, 学习 Rust, Rust 入门, 为什么 Rust
npx skills add actionbook/rust-skills --skill m14-mental-model
Layer 2: Design Choices
What's the right way to think about this Rust concept?
When learning or explaining Rust:
| Concept | Mental Model | Analogy |
|---|---|---|
| Ownership | Unique key | Only one person has the house key |
| Move | Key handover | Giving away your key |
&T | Lending for reading | Lending a book |
&mut T | Exclusive editing | Only you can edit the doc |
Lifetime 'a | Valid scope | "Ticket valid until..." |
Box<T> | Heap pointer | Remote control to TV |
Rc<T> | Shared ownership | Multiple remotes, last turns off |
Arc<T> | Thread-safe Rc | Remotes from any room |
| From | Key Shift |
|---|---|
| Java/C# | Values are owned, not references by default |
| C/C++ | Compiler enforces safety rules |
| Python/Go | No GC, deterministic destruction |
| Functional | Mutability is safe via ownership |
| JavaScript | No null, use Option instead |
When confused about Rust:
What's the ownership model?
What guarantee is Rust providing?
What's the compiler telling me?
To design understanding (Layer 2):
To implementation (Layer 1):
| Error | Wrong Model | Correct Model |
|---|---|---|
| E0382 use after move | GC cleans up | Ownership = unique key transfer |
| E0502 borrow conflict | Multiple writers OK | Only one writer at a time |
| E0499 multiple mut borrows | Aliased mutation | Exclusive access for mutation |
| E0106 missing lifetime | Ignoring scope | References have validity scope |
E0507 cannot move from &T | Implicit clone | References don't own data |
| Deprecated | Better |
|---|---|
| "Rust is like C++" | Different ownership model |
| "Lifetimes are GC" | Compile-time validity scope |
| "Clone solves everything" | Restructure ownership |
| "Fight the borrow checker" | Work with the compiler |
"unsafe to avoid rules" | Understand safe patterns first |
| Stage | Focus | Skills |
|---|---|---|
| Beginner | Ownership basics | m01-ownership, m14-mental-model |
| Intermediate | Smart pointers, error handling | m02, m06 |
| Advanced | Concurrency, unsafe | m07, unsafe-checker |
| Expert | Design patterns | m09-m15, domain-* |
| When | See |
|---|---|
| Ownership errors | m01-ownership |
| Smart pointers | m02-resource |
| Concurrency | m07-concurrency |
| Anti-patterns | m15-anti-pattern |
+----------------+
| data: String |────────────> "hello"
+----------------+
↑
│ &data (immutable borrow)
│
+------+------+
| reader1 reader2 (multiple OK)
+------+------+
+----------------+
| data: String |────────────> "hello"
+----------------+
↑
│ &mut data (mutable borrow)
│
+------+
| writer (only one)
+------+