Architecture Rules

MVT architecture rules have moved to the Architecture section. This page provides quick-reference tables linking each rule to its documentation.

See: Architecture Rules (full) - Style Guide - Glossary

Universal MVT Rules

These apply to any MVT implementation regardless of language or renderer. The canonical definitions live in Architecture Rules.

Rule	Constraint	Reference
M-time	All state advances through `update(deltaMs)` only	Architecture Rules
M-isolation	Models must not reference views or the ticker	Architecture Rules
M-domain	State uses domain-level terms, not presentation terms	Architecture Rules
M-composition	Parent models delegate `update(deltaMs)` to children	Architecture Rules

Rule	Constraint	Reference
V-stateless	Views hold no domain state	Architecture Rules
V-refresh	`refresh()` runs once per frame, after all models have updated	Architecture Rules
V-idempotent	`refresh()` must be idempotent	Architecture Rules
V-readonly	`refresh()` must not mutate models	Architecture Rules
V-reactive	Query bindings given as functions must be re-read in `refresh()`, never cached	Architecture Rules
V-presentation	Views may hold cosmetic presentation state the model does not track	Architecture Rules
V-output	Views can target any output technology	Architecture Rules
V-tree	View trees do not need to mirror model trees	Architecture Rules

Rule	Constraint	Reference
T-sequence	Each frame follows strict order: update, advance view state, refresh, render	Architecture Rules
T-cap	Cap `deltaMs` to a safe maximum	Architecture Rules
T-minimal	The ticker contains no domain logic and no rendering code	Architecture Rules
T-control	The ticker may pause, slow, speed up, or single-step time	Architecture Rules

Rule	Constraint	Reference
B-contract	Bindings are the contract between a view and the world	Architecture Rules
B-reusable	Reusable leaf views use a bindings interface; top-level views may access models directly	Architecture Rules
B-optional	Relay bindings should usually be optional	Architecture Rules
B-wiring	Bindings are wired at the view construction site	Architecture Rules

Rule	Constraint	Reference
H-cost	Minimise per-tick computation cost	Architecture Rules
H-alloc	Avoid per-tick heap allocations in `update()` and `refresh()`	Architecture Rules
H-loops	Use index-based loops and pre-allocated structures	Architecture Rules
H-change	Use change detection for rare but expensive updates	Architecture Rules

These are style and structural choices for this project, not MVT requirements. See the Style Guide for full details.

Convention	Reference
Factory functions, not classes	Style Guide
String-literal unions, not `enum`	Style Guide
`Kind` not `Type`, `phase` not `state`	Style Guide
Barrel imports only	Project Structure
4-space indentation	Style Guide