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//! 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.
extern crate assert_approx_eq;
extern crate indoc;
// We need those types in the macro exports
pub extern crate libc;
// We need that reexport for wrap_function
pub extern crate mashup;
extern crate pyo3cls;
extern crate spin;
pub use crate*;
pub use crate;
pub use crate;
pub use crate;
pub use crate NoArgs;
pub use crate PyObject;
pub use crate ObjectProtocol;
pub use crate;
pub use crate;
pub use crate;
pub use crate exceptions;
/// Rust FFI declarations for Python
/// Constructs a `&'static CStr` literal.
/// The proc macros, which are also part of the prelude
/// Returns a function that takes a [Python] instance and returns a python function.
///
/// Use this together with `#[function]` and [types::PyModule::add_function].