Quick reference for symbols, notation, and abbreviations the book uses. Concept definitions live in the glossary; this page covers the shorthand only.
| Symbol | Meaning |
|---|
| §N | Section number — e.g., §5 refers to section 5. |
| → | Leads to / becomes / transitions to. Appears in section titles (e.g., §29 “10K → 1M”) and prose. |
[!NOTE] / [!TIP] / [!WARNING] | Callout box — content the reader should pay particular attention to. |
| Form | Meaning |
|---|
monospace | Code: types, variable names, function names, file paths. |
| italic | First definition of a term, or emphasis. |
| bold | A term being highlighted as load-bearing in the current paragraph. |
| Variable | Meaning |
|---|
i, j | Index into a table. i is the index of the row currently under discussion. |
t or tick | Tick number — the simulator’s step counter. |
id | Stable entity identifier (an integer). |
gen | Generation counter, paired with a slot index to detect stale references (§10). |
pos, vel | Position and velocity of a creature. |
to_remove, to_insert | Buffers of pending mutations applied at end-of-tick (§22). |
| Type | What it is |
|---|
Vec<T> | Heap-allocated, growable array of T. The book’s “table.” |
&[T] | Read-only borrow of a contiguous slice. |
&mut [T] | Mutable borrow of a contiguous slice. |
usize | Pointer-sized unsigned integer. Used for table indices. |
u8 / u16 / u32 / u64 | Unsigned integers, sized in bits. |
f32 / f64 | 32-bit and 64-bit floats. |
| Acronym | Expanded |
|---|
| ECS | Entity-Component-Systems |
| EBP | Existence-Based Processing |
| DOD | Data-Oriented Design |
| SoA | Structure of Arrays — each field is its own column. |
| AoS | Array of Structures — each row is its own struct. |
| DAG | Directed Acyclic Graph |
| IOPS | I/O Operations Per Second |
| TDD | Test-Driven Development |
| LRU | Least Recently Used (cache eviction policy) |
snake_case for variables, functions, fields.PascalCase for types and traits.SCREAMING_SNAKE for constants.- File names mirror their dominant content:
creatures.rs defines the creature table, motion.rs the motion system.