Proc macro documentation

pyo3-macros/src/lib.rs

@@ -13,8 +13,10 @@ use pyo3_macros_backend::{
 use quote::quote;
 use syn::parse_macro_input;
 
-/// Internally, this proc macro create a new c function called `PyInit_{my_module}`
-/// that then calls the init function you provided
+/// A proc macro used to implement Python modules.
+///
+/// For more on creating Python modules
+/// see the [module section of the guide](https://pyo3.rs/main/module.html).
 #[proc_macro_attribute]
 pub fn pymodule(attr: TokenStream, input: TokenStream) -> TokenStream {
     let mut ast = parse_macro_input!(input as syn::ItemFn);
@@ -43,6 +45,16 @@ pub fn pymodule(attr: TokenStream, input: TokenStream) -> TokenStream {
     .into()
 }
 
+/// A proc macro used to implement Python's [dunder methods][1].
+///
+/// This atribute is required on blocks implementing [`PyObjectProtocol`][2],
+/// [`PyNumberProtocol`][3], [`PyGCProtocol`][4] and [`PyIterProtocol`][5].
+///
+/// [1]: https://docs.python.org/3/reference/datamodel.html#special-method-names
+/// [2]: ../class/basic/trait.PyObjectProtocol.html
+/// [3]: ../class/number/trait.PyNumberProtocol.html
+/// [4]: ../class/gc/trait.PyGCProtocol.html
+/// [5]: ../class/iter/trait.PyIterProtocol.html
 #[proc_macro_attribute]
 pub fn pyproto(_: TokenStream, input: TokenStream) -> TokenStream {
     let mut ast = parse_macro_input!(input as syn::ItemImpl);
@@ -55,26 +67,152 @@ pub fn pyproto(_: TokenStream, input: TokenStream) -> TokenStream {
     .into()
 }
 
+/// A proc macro used to expose Rust structs as Python objects.
+///
+/// `#[pyclass]` accepts the following [parameters][2]:
+///
+/// |  Parameter  |  Description |
+/// | :-  | :- |
+/// | `name = "python_name"` | Sets the name that Python sees this class as. Defaults to the name of the Rust struct. |
+/// | `freelist = N`  |  Implements a [free list][10] of size N. This can improve performance for types that are often created and deleted in a row. Profile your code to see whether `freelist` is right for you.  |
+/// | `gc`  | Participate in Python's [garbage collection][5]. Required if your type contains references to other Python objects. If you don't (or incorrectly) implement this, contained Python objects may be hidden from Python's garbage collector and you may leak memory. Note that leaking memory, while undesirable, [is safe behavior][7].|
+/// | `weakref` | Allows this class to be [weakly referenceable][6]. |
+/// | `extends = BaseType`  | Use a custom baseclass. Defaults to [`PyAny`][4] |
+/// | `subclass` | Allows Python classes to inherit from this class.  |
+/// | `unsendable`<!-- hack to stop the column from wrapping -->&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; | Required if your struct is not [`Send`][3]. Rather than using `unsendable`, consider implementing your struct in a threadsafe way by e.g. substituting [`Rc`][8] with [`Arc`][9]. By using `unsendable`, your class will panic when accessed by another thread.|
+/// | `module = "module_name"` |  Python code will see the class as being defined in this module. Defaults to `builtins`. |
+///
+/// For more on creating Python classes,
+/// see the [class section of the guide][1].
+///
+/// [1]: https://pyo3.rs/main/class.html
+/// [2]: https://pyo3.rs/main/class.html#customizing-the-class
+/// [3]: std::marker::Send
+/// [4]: ../prelude/struct.PyAny.html
+/// [5]: https://pyo3.rs/main/class/protocols.html#garbage-collector-integration
+/// [6]: https://docs.python.org/3/library/weakref.html
+/// [7]: https://doc.rust-lang.org/nomicon/leaking.html
+/// [8]: std::rc::Rc
+/// [9]: std::sync::Arc
+/// [10]: https://en.wikipedia.org/wiki/Free_list
 #[proc_macro_attribute]
 pub fn pyclass(attr: TokenStream, input: TokenStream) -> TokenStream {
     pyclass_impl(attr, input, PyClassMethodsType::Specialization)
 }
 
+/// A proc macro used to expose Rust structs as Python objects.
+///
+/// `#[pyclass]` accepts the following [parameters][2]:
+///
+/// |  Parameter  |  Description |
+/// | :-  | :- |
+/// | `name = "python_name"` | Sets the name that Python sees this class as. Defaults to the name of the Rust struct. |
+/// | `freelist = N`  |  Implements a [free list][10] of size N. This can improve performance for types that are often created and deleted in a row. Profile your code to see whether `freelist` is right for you.  |
+/// | `gc`  | Participate in Python's [garbage collection][5]. Required if your type contains references to other Python objects. If you don't (or incorrectly) implement this, contained Python objects may be hidden from Python's garbage collector and you may leak memory. Note that leaking memory, while undesirable, [is safe behavior][7].|
+/// | `weakref` | Allows this class to be [weakly referenceable][6]. |
+/// | `extends = BaseType`  | Use a custom baseclass. Defaults to [`PyAny`][4] |
+/// | `subclass` | Allows Python classes to inherit from this class.  |
+/// | `unsendable`<!-- hack to stop the column from wrapping -->&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; | Required if your struct is not [`Send`][3]. Rather than using `unsendable`, consider implementing your struct in a threadsafe way by e.g. substituting [`Rc`][8] with [`Arc`][9]. By using `unsendable`, your class will panic when accessed by another thread.|
+/// | `module = "module_name"` |  Python code will see the class as being defined in this module. Defaults to `builtins`. |
+///
+/// For more on creating Python classes,
+/// see the [class section of the guide][1].
+///
+/// [1]: https://pyo3.rs/main/class.html
+/// [2]: https://pyo3.rs/main/class.html#customizing-the-class
+/// [3]: std::marker::Send
+/// [4]: ../prelude/struct.PyAny.html
+/// [5]: https://pyo3.rs/main/class/protocols.html#garbage-collector-integration
+/// [6]: https://docs.python.org/3/library/weakref.html
+/// [7]: https://doc.rust-lang.org/nomicon/leaking.html
+/// [8]: std::rc::Rc
+/// [9]: std::sync::Arc
+/// [10]: https://en.wikipedia.org/wiki/Free_list
 #[proc_macro_attribute]
 pub fn pyclass_with_inventory(attr: TokenStream, input: TokenStream) -> TokenStream {
     pyclass_impl(attr, input, PyClassMethodsType::Inventory)
 }
 
+/// A proc macro used to expose methods to Python.
+///
+/// Methods within a `#[pymethods]` block can be annotated with the following:
+///
+/// |  Annotation  |  Description |
+/// | :-  | :- |
+/// | [`#[new]`][4]  | Defines the class constructor, like Python's `__new__` method. |
+/// | [`#[getter]`][5] and [`#[setter]`][5] | These define getters and setters, similar to Python's `@property` decorator. This is useful for getters/setters that require computation or side effects; if that is not the case consider using [`#[pyo3(get, set)]`][11] on the struct's field(s).|
+/// | [`#[staticmethod]`][6]| Defines the method as a staticmethod, like Python's `@staticmethod` decorator.|
+/// | [`#[classmethod]`][7]  | Defines the method as a classmethod, like Python's `@classmethod` decorator.|
+/// | [`#[call]`][8]  | Allows Python code to call a class instance as a function, like Python's `__call__` method. |
+/// | [`#[classattr]`][9]  | Defines a class variable. |
+/// | [`#[args]`][10]  | Define a method's default arguments and allows the function to receive `*args` and `**kwargs`.  |
+///
+/// For more on creating class methods,
+/// see the [class section of the guide][1].
+///
+/// If the [`multiple-pymethods`][2] feature is enabled, it is possible to implement
+/// multiple `#[pymethods]` blocks for a single `#[pyclass]`.
+/// This will add a transitive dependency on the [`inventory`][3] crate.
+///
+/// [1]: https://pyo3.rs/main/class.html#instance-methods
+/// [2]: https://pyo3.rs/main/features.html#multiple-pymethods
+/// [3]: https://docs.rs/inventory/
+/// [4]: https://pyo3.rs/main/class.html#constructor
+/// [5]: https://pyo3.rs/main/class.html#object-properties-using-getter-and-setter
+/// [6]: https://pyo3.rs/main/class.html#static-methods
+/// [7]: https://pyo3.rs/main/class.html#class-methods
+/// [8]: https://pyo3.rs/main/class.html#callable-objects
+/// [9]: https://pyo3.rs/main/class.html#class-attributes
+/// [10]: https://pyo3.rs/main/class.html#method-arguments
+/// [11]: https://pyo3.rs/main/class.html#object-properties-using-pyo3get-set
 #[proc_macro_attribute]
 pub fn pymethods(_: TokenStream, input: TokenStream) -> TokenStream {
     pymethods_impl(input, PyClassMethodsType::Specialization)
 }
 
+/// A proc macro used to expose methods to Python.
+///
+/// Methods within a `#[pymethods]` block can be annotated with the following:
+///
+/// |  Annotation  |  Description |
+/// | :-  | :- |
+/// | [`#[new]`][4]  | Defines the class constructor, like Python's `__new__` method. |
+/// | [`#[getter]`][5] and [`#[setter]`][5] | These define getters and setters, similar to Python's `@property` decorator. This is useful for getters/setters that require computation or side effects; if that is not the case consider using [`#[pyo3(get, set)]`][11] on the struct's field(s).|
+/// | [`#[staticmethod]`][6]| Defines the method as a staticmethod, like Python's `@staticmethod` decorator.|
+/// | [`#[classmethod]`][7]  | Defines the method as a classmethod, like Python's `@classmethod` decorator.|
+/// | [`#[call]`][8]  | Allows Python code to call a class instance as a function, like Python's `__call__` method. |
+/// | [`#[classattr]`][9]  | Defines a class variable. |
+/// | [`#[args]`][10]  | Define a method's default arguments and allows the function to receive `*args` and `**kwargs`.  |
+///
+/// For more on creating class methods,
+/// see the [class section of the guide][1].
+///
+/// If the [`multiple-pymethods`][2] feature is enabled, it is possible to implement
+/// multiple `#[pymethods]` blocks for a single `#[pyclass]`.
+/// This will add a transitive dependency on the [`inventory`][3] crate.
+///
+/// [1]: https://pyo3.rs/main/class.html#instance-methods
+/// [2]: https://pyo3.rs/main/features.html#multiple-pymethods
+/// [3]: https://docs.rs/inventory/
+/// [4]: https://pyo3.rs/main/class.html#constructor
+/// [5]: https://pyo3.rs/main/class.html#object-properties-using-getter-and-setter
+/// [6]: https://pyo3.rs/main/class.html#static-methods
+/// [7]: https://pyo3.rs/main/class.html#class-methods
+/// [8]: https://pyo3.rs/main/class.html#callable-objects
+/// [9]: https://pyo3.rs/main/class.html#class-attributes
+/// [10]: https://pyo3.rs/main/class.html#method-arguments
+/// [11]: https://pyo3.rs/main/class.html#object-properties-using-pyo3get-set
 #[proc_macro_attribute]
 pub fn pymethods_with_inventory(_: TokenStream, input: TokenStream) -> TokenStream {
     pymethods_impl(input, PyClassMethodsType::Inventory)
 }
 
+/// A proc macro used to expose Rust functions to Python.
+///
+/// For more on exposing functions,
+/// see the [function section of the guide][1].
+///
+/// [1]: https://pyo3.rs/main/function.html
 #[proc_macro_attribute]
 pub fn pyfunction(attr: TokenStream, input: TokenStream) -> TokenStream {
     let mut ast = parse_macro_input!(input as syn::ItemFn);

src/lib.rs

@@ -190,11 +190,13 @@ pub mod types;
 #[cfg(feature = "serde")]
 pub mod serde;
 
-/// The proc macros, which are also part of the prelude.
+/// The proc macros, all of which are part of the prelude.
+///
+/// Import these with `use pyo3::prelude::*;`
 #[cfg(feature = "macros")]
 pub mod proc_macro {
     pub use pyo3_macros::pymodule;
-    /// The proc macro attributes
+
     pub use pyo3_macros::{pyfunction, pyproto};
 
     #[cfg(not(feature = "multiple-pymethods"))]