library

name	library
description	How the Faebryk component library is structured, how `_F.py` is generated, and the conventions/invariants for adding new library modules. Use when adding or modifying library components, traits, or module definitions.

Library Module

The library module (located in src/faebryk/library/) contains the collection of reusable components, traits, and interfaces that form the "standard library" of the hardware design language.

Quick Start

import faebryk.core.faebrykpy as fbrk
import faebryk.core.graph as graph
import faebryk.library._F as F

g = graph.GraphView.create()
tg = fbrk.TypeGraph.create(g=g)

resistor = F.Resistor.bind_typegraph(tg=tg).create_instance(g=g)

Relevant Files

• Facade (auto-generated): src/faebryk/library/_F.py
  • Eagerly imports and re-exports library modules/types for the import faebryk.library._F as F pattern.
  • This file is generated; do not hand-edit it.
• Generator: tools/library/gen_F.py
  • Scans src/faebryk/library/*.py, detects whether the file contains a same-named class, and writes _F.py.
  • Orders exports via a topological sort of F.<Name> references to avoid import-order cycles.
• Components: src/faebryk/library/ contains specific component definitions (e.g. Resistor.py, Capacitor.py, LED.py).
• Traits/Interfaces: Also contains trait definitions (e.g. can_bridge.py, is_power.py).

Dependants (Call Sites)

• User Code: atopile projects heavily import from faebryk.library._F (aliased as F).
• Compiler: The compiler maps ato built-ins to these classes.

How to Work With / Develop / Test

Core Concepts

• Traits vs Components: Use Traits for behavior (what it can do like can_bridge) and Components for physical things (what it is like Resistor).
• Export model: _F.py is a generated “barrel” module; importing it is intentionally convenient but can be heavyweight.

Development Workflow

1. New Component: Create a new file MyComponent.py in src/faebryk/library/. Inherit from Node (or a more specific base).
2. Naming Convention: Class names should match the file basename (usually).
3. Regenerate _F.py: run python tools/library/gen_F.py and commit the updated src/faebryk/library/_F.py.

Testing

• Library tests live under test/library/ (including test/library/nodes/).
• A good smoke test for new modules is:
  • ato dev test --llm test/library/test_instance_library_modules.py -q

Best Practices

• Atomic Parts: Mark leaf components (specifically verified part numbers) with the is_atomic_part trait.
• Parameters: Use F.Parameters to define physical properties like resistance, capacitance, etc.
• Documentation: Add docstrings to components explaining their ports and parameters.