#pyo3 #derive #dict

macro dict_derive

Derive macros for some PyO3 traits to convert python dicts into rust structs

4 releases

✓ Uses Rust 2018 edition

new 0.2.0 Sep 11, 2019
0.1.2 Sep 11, 2019
0.1.1 Jun 16, 2019
0.1.0 Jun 13, 2019

#38 in FFI

39 downloads per month


152 lines


Derive macro for PyO3's FromPyObject and IntoPy<PyObject> traits. The derived implementation turns a Python's dict into your Rust struct and back.


Add the library to your Cargo.toml together with PyO3:

pyo3 = "0.8.0"
dict_derive = "0.2.0"

Import the derive implementation and use it on your structs:

extern crate dict_derive;

use dict_derive::{FromPyObject, IntoPyObject};

#[derive(FromPyObject, IntoPyObject)]
struct User {
    name: String,
    email: String,
    age: u32,

Then you can use your structs as arguments and return values in your PyO3 functions:

extern crate pyo3;
use pyo3::prelude::*;
use pyo3::wrap_pyfunction;

// Requires FromPyObject to receive a struct as an argument
fn get_contact_info(user: User) -> PyResult<String> {
    Ok(format!("{} - {}", user.name, user.email))

// Requires IntoPyObject to return a struct
fn get_default_user() -> PyResult<User> {
    Ok(User {
        name: "Default".to_owned(),
        email: "default@user.com".to_owned(),
        age: 27,

And then call your functions using normal python dicts:

>>> import mylib
>>> mylib.get_contact_info({"name": "Thor", "email": "thor@asgard.com", "age": 23})
'Thor - thor@asgard.com'
>>> mylib.get_default_user()
{'name': 'Default', 'email': 'default@user.com', 'age': 27}

Older PyO3 versions

For PyO3 version 0.7.0 or lower, use version 0.1 of this crate.


~22K SLoC