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
monospaceCode: 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, jIndex into a table. i is the index of the row currently under discussion. t or tickTick number - the simulator’s step counter. idStable entity identifier (an integer). genGeneration counter, paired with a slot index to detect stale references (§10). pos, velPosition and velocity of a creature. to_remove, to_insertBuffers 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. usizePointer-sized unsigned integer. Used for table indices. u8 / u16 / u32 / u64Unsigned integers, sized in bits. f32 / f6432-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)
EBP is this book’s shorthand. The spelled-out term - existence-based processing - is Richard Fabian’s, from Data-Oriented Design
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.