facet-python

Crates.io	facet-python
lib.rs	facet-python
version	0.43.2
created_at	2026-01-22 16:54:28.557305+00
updated_at	2026-01-23 18:06:40.74262+00
description	Generate Python type definitions from facet type metadata
homepage	https://facet.rs
repository	https://github.com/facet-rs/facet
max_upload_size
id	2062165
size	57,348

Amos Wenger (fasterthanlime)

documentation

README

facet-python

Generate Python type definitions from facet type metadata.

Overview

This crate uses facet's reflection capabilities to generate Python type hints and TypedDicts from any Rust type that implements Facet. This enables type-safe interop when your Rust code exchanges data with Python.

Example

use facet::Facet;
use facet_python::to_python;

#[derive(Facet)]
struct User {
    name: String,
    age: u32,
    email: Option<String>,
}

let python_code = to_python::<User>(false);

This generates:

from typing import TypedDict, Required, NotRequired

class User(TypedDict, total=False):
    name: Required[str]
    age: Required[int]
    email: str  # Optional fields become NotRequired

Type Mappings

Rust Type	Python Type
`String`, `&str`	`str`
`i32`, `u32`, etc.	`int`
`f32`, `f64`	`float`
`bool`	`bool`
`Vec<T>`	`list[T]`
`Option<T>`	`T` (NotRequired in TypedDict)
`HashMap<K, V>`	`dict[K, V]`
Struct	`TypedDict`
Enum	`Union[...]` of variants

Features

Recursive types: Handles nested structs and enums
Documentation: Preserves doc comments as Python docstrings
Reserved keywords: Automatically handles Python reserved words as field names
Generic support: Maps Rust generics to Python type parameters