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#![feature(specialization)] //! Rust bindings to the Python interpreter. //! //! # Ownership and Lifetimes //! In Python, all objects are implicitly reference counted. //! In rust, we will use the `PyObject` type to represent a reference to a Python object. //! //! Because all Python objects potentially have multiple owners, the //! concept of Rust mutability does not apply to Python objects. //! As a result, this API will allow mutating Python objects even if they are not stored //! in a mutable Rust variable. //! //! The Python interpreter uses a global interpreter lock (GIL) //! to ensure thread-safety. //! This API uses a zero-sized `struct Python<'p>` as a token to indicate //! that a function can assume that the GIL is held. //! //! You obtain a `Python` instance by acquiring the GIL, //! and have to pass it into all operations that call into the Python runtime. //! //! # Error Handling //! The vast majority of operations in this library will return `PyResult<...>`. //! This is an alias for the type `Result<..., PyErr>`. //! //! A `PyErr` represents a Python exception. Errors within the `PyO3` library are //! also exposed as Python exceptions. //! //! # Example //! //! ```rust //! #![feature(specialization)] //! //! extern crate pyo3; //! //! use pyo3::prelude::*; //! use pyo3::types::PyDict; //! //! fn main() -> PyResult<()> { //! let gil = Python::acquire_gil(); //! let py = gil.python(); //! let sys = py.import("sys")?; //! let version: String = sys.get("version")?.extract()?; //! //! let locals = PyDict::new(py); //! locals.set_item("os", py.import("os")?)?; //! let code = "os.getenv('USER') or os.getenv('USERNAME') or 'Unknown'"; //! let user: String = py.eval(code, None, Some(&locals))?.extract()?; //! //! println!("Hello {}, I'm Python {}", user, version); //! Ok(()) //! } //! ``` //! //! # Python extension //! //! To allow Python to load the rust code as a Python extension //! module, you need an initialization function with `Fn(Python, &PyModule) -> PyResult<()>` //! that is annotates with `#[pymodinit]`. By default the function name will become the module name, //! but you can override that with `#[pymodinit(name)]`. //! //! To creates a Python callable object that invokes a Rust function, specify rust //! function and decorate it with `#[pyfn()]` attribute. `pyfn()` accepts three parameters. //! //! 1. `m`: The module name. //! 2. name of function visible to Python code. //! 3. comma separated arguments, i.e. param="None", "*", param3="55" //! //! //! # Example //! //! ```rust //! #![feature(specialization)] //! //! extern crate pyo3; //! use pyo3::prelude::*; //! //! // Add bindings to the generated python module //! // N.B: names: "librust2py" must be the name of the `.so` or `.pyd` file //! /// This module is implemented in Rust. //! #[pymodinit] //! fn rust2py(py: Python, m: &PyModule) -> PyResult<()> { //! //! #[pyfn(m, "sum_as_string")] //! // ``#[pyfn()]` converts the arguments from Python objects to Rust values //! // and the Rust return value back into a Python object. //! fn sum_as_string_py(a:i64, b:i64) -> PyResult<String> { //! let out = sum_as_string(a, b); //! Ok(out) //! } //! //! Ok(()) //! } //! //! // The logic can be implemented as a normal rust function //! fn sum_as_string(a:i64, b:i64) -> String { //! format!("{}", a + b).to_string() //! } //! //! # fn main() {} //! ``` //! //! In your `Cargo.toml`, use the `extension-module` feature for the `pyo3` dependency: //! //! ```cargo //! [dependencies.pyo3] //! version = "*" //! features = ["extension-module"] //! ``` //! //! On windows and linux, you can build normally with `cargo build --release`. On Mac Os, you need to set additional linker arguments. One option is to compile with `cargo rustc --release -- -C link-arg=-undefined -C link-arg=dynamic_lookup`, the other is to create a `.cargo/config` with the following content: //! //! ```toml //! [target.x86_64-apple-darwin] //! rustflags = [ //! "-C", "link-arg=-undefined", //! "-C", "link-arg=dynamic_lookup", //! ] //! ``` //! //! Also on macOS, you will need to rename the output from \*.dylib to \*.so. On Windows, you will need to rename the output from \*.dll to \*.pyd. //! //! [`setuptools-rust`](https://github.com/PyO3/setuptools-rust) can be used to generate a python package and includes the commands above by default. See [examples/word-count](examples/word-count) and the associated setup.py. #[cfg(test)] #[macro_use] extern crate assert_approx_eq; #[cfg(test)] #[macro_use] extern crate indoc; // We need those types in the macro exports #[doc(hidden)] pub extern crate libc; // We need that reexport for wrap_function #[doc(hidden)] pub extern crate mashup; extern crate pyo3cls; extern crate spin; pub use crate::class::*; pub use crate::conversion::{ FromPyObject, IntoPyObject, IntoPyTuple, PyTryFrom, PyTryInto, ReturnTypeIntoPyResult, ToBorrowedObject, ToPyObject, }; pub use crate::err::{PyDowncastError, PyErr, PyErrArguments, PyErrValue, PyResult}; pub use crate::instance::{AsPyRef, Py, PyNativeType, PyObjectWithToken, PyToken}; pub use crate::noargs::NoArgs; pub use crate::object::PyObject; pub use crate::objectprotocol::ObjectProtocol; pub use crate::python::{IntoPyPointer, Python, ToPyPointer}; pub use crate::pythonrun::{init_once, prepare_freethreaded_python, GILGuard, GILPool}; pub use crate::typeob::{PyObjectAlloc, PyRawObject, PyTypeInfo}; pub use crate::types::exceptions; /// Rust FFI declarations for Python pub mod ffi; #[cfg(not(Py_3))] mod ffi2; #[cfg(Py_3)] mod ffi3; pub mod class; /// Constructs a `&'static CStr` literal. macro_rules! cstr { ($s: tt) => { // TODO: verify that $s is a string literal without nuls unsafe { ::std::ffi::CStr::from_ptr(concat!($s, "\0").as_ptr() as *const _) } }; } pub mod buffer; #[doc(hidden)] pub mod callback; mod conversion; #[doc(hidden)] pub mod derive_utils; mod err; pub mod freelist; mod instance; mod noargs; mod object; mod objectprotocol; pub mod prelude; pub mod python; mod pythonrun; pub mod typeob; pub mod types; /// The proc macros, which are also part of the prelude pub mod proc_macro { #[cfg(not(Py_3))] pub use pyo3cls::mod2init as pymodinit; #[cfg(Py_3)] pub use pyo3cls::mod3init as pymodinit; /// The proc macro attributes pub use pyo3cls::{pyclass, pyfunction, pymethods, pyproto}; } /// Returns a function that takes a [Python] instance and returns a python function. /// /// Use this together with `#[function]` and [types::PyModule::add_function]. #[macro_export] macro_rules! wrap_function { ($function_name:ident) => {{ // Get the mashup macro and its helpers into scope use $crate::mashup::*; mashup! { // Make sure this ident matches the one in function_wrapper_ident m["method"] = __pyo3_get_function_ $function_name; } m! { &"method" } }}; }