Rust Project Structure Rules

This file defines the preferred Rust project organization for this repo.

Core Principles

1. Organize by domain and feature, not by type.
2. Keep orchestration glue in app/.
3. Split always-on logic into core/ and optional capabilities into features/.
4. Each subdomain under core/ and each feature under features/ must be its own folder with clear boundaries.
5. Only add feature files that the feature actually needs (state.rs, render.rs, ui.rs, helpers.rs).
6. Avoid type-based folders like constructors/, methods/, traits/, or enums/.

Top-Level Layout (Typical)

src/
├── lib.rs
├── main.rs
├── app/                 # orchestration, wiring, lifecycle
├── core/                # always-on domain + engine
├── features/            # optional capabilities
├── adapters/            # external boundaries (db, http, fs, cli)
├── services/            # infra helpers (watchers, git, timers)
├── config/              # config structs + loaders
└── utils/               # tiny pure helpers only

Top-Level Layout (TUI)

src/
├── main.rs
├── app/                 # orchestration, event loop, wiring
├── widgets/             # widget modules (primary organization)
├── screens/             # view composition
├── adapters/            # external boundaries (fs, git, clipboard)
├── services/            # infra helpers (file watching, timers)
├── config/              # config structs + loaders
└── utils/               # tiny pure helpers only

Folder Semantics

• app/: glue layer. Composition, wiring, lifecycle, and startup/teardown.
  • Web: router.rs, lifecycle.rs
  • TUI: event_loop.rs, layout_wiring.rs
• core/: required engine logic that defines the domain (non-TUI).
  • Web: core/model/, core/engine/
• features/: optional or additive capabilities (non-TUI). Each feature is a folder.
  • Web: features/auth/, features/settings/
  • TUI: features/toc/, features/scrollbar
• widgets/: primary TUI organization unit. Each widget is a bounded folder.
  • TUI: widgets/markdown_widget/, widgets/command_palette/
• screens/: TUI view composition and layout wiring.
  • TUI: screens/dashboard.rs, screens/settings.rs
• adapters/: outbound/inbound boundaries to external systems (storage is a kind of adapter).
  • Web: adapters/http.rs, adapters/storage.rs
  • TUI: adapters/fs.rs, adapters/git.rs
• services/: internal infrastructure helpers (file watching, git status, timers).
  • Web: services/timer.rs, services/clock.rs
  • TUI: services/file_watcher.rs, services/git_status.rs
• config/: config structs + loaders.
  • Web: config/app_config.rs
  • TUI: config/tui_config.rs
• utils/: tiny pure helpers only. No IO, no shared state.
  • Web: utils/format.rs
  • TUI: utils/geometry.rs

Core Structure (Subdomain Boundaries)

Each core subdomain is its own folder. Keep code flat inside unless it grows.

src/core/
├── mod.rs
├── model/
├── engine/
├── parser/
├── render/
├── source/
├── events/
└── types/

Feature Structure (Feature Boundaries)

Each feature is a folder. Add state.rs, render.rs, ui.rs, or helpers.rs only when the feature needs them.

src/features/
├── mod.rs
├── toc/
│   ├── mod.rs
│   ├── state.rs
│   ├── render.rs
│   └── helpers.rs
├── selection/
│   ├── mod.rs
│   ├── state.rs
│   └── helpers.rs
└── theme/
    ├── mod.rs
    ├── palette.rs
    ├── style.rs
    └── load.rs

File Naming

1. Use snake_case filenames.
2. Filename matches the primary type or concern.
3. One logical concern per file.

Example Structures

Example: CLI App

src/
├── main.rs
├── app/
│   ├── mod.rs
│   ├── bootstrap.rs
│   └── wiring.rs
├── core/
│   ├── mod.rs
│   ├── model/
│   ├── parser/
│   └── engine/
├── features/
│   ├── mod.rs
│   ├── search/
│   │   ├── mod.rs
│   │   └── state.rs
│   └── export/
│       ├── mod.rs
│       └── helpers.rs
├── adapters/
│   ├── mod.rs
│   ├── cli.rs
│   └── fs.rs
├── services/
│   ├── mod.rs
│   └── file_watcher.rs
└── config/
    ├── mod.rs
    └── settings.rs

Example: Web App (Dioxus)

src/
├── main.rs
├── app/
│   ├── mod.rs
│   ├── router.rs
│   └── wiring.rs
├── core/
│   ├── mod.rs
│   ├── model/
│   ├── engine/
│   └── events/
├── features/
│   ├── mod.rs
│   ├── auth/
│   │   ├── mod.rs
│   │   ├── state.rs
│   │   └── ui.rs
│   ├── dashboard/
│   │   ├── mod.rs
│   │   └── ui.rs
│   └── settings/
│       ├── mod.rs
│       └── ui.rs
├── adapters/
│   ├── mod.rs
│   └── http.rs
└── services/
    ├── mod.rs
    └── storage.rs

Example: TUI App (ratatui)

src/
├── main.rs
├── app/
│   ├── mod.rs
│   ├── lifecycle.rs
│   └── wiring.rs
├── screens/
│   ├── mod.rs
│   ├── dashboard.rs
│   └── settings.rs
├── widgets/
│   ├── mod.rs
│   ├── markdown_widget/
│   │   ├── mod.rs
│   │   ├── widget/
│   │   ├── state/
│   │   ├── foundation/
│   │   └── extensions/
│   └── command_palette/
│       ├── mod.rs
│       ├── state.rs
│       └── render.rs
├── adapters/
│   ├── mod.rs
│   └── fs.rs
└── services/
    ├── mod.rs
    └── file_watcher.rs