diff --git a/src/libstd/keyword_docs.rs b/src/libstd/keyword_docs.rs index a4996d9eee810..6d98c4d01c040 100644 --- a/src/libstd/keyword_docs.rs +++ b/src/libstd/keyword_docs.rs @@ -1009,9 +1009,93 @@ mod return_keyword {} // /// The receiver of a method, or the current module. /// -/// The documentation for this keyword is [not yet complete]. Pull requests welcome! +/// `self` is used in two situations: referencing the current module and marking +/// the receiver of a method. /// -/// [not yet complete]: https://github.com/rust-lang/rust/issues/34601 +/// In paths, `self` can be used to refer to the current module, either in a +/// [`use`] statement or in a path to access an element: +/// +/// ``` +/// # #![allow(unused_imports)] +/// use std::io::{self, Read}; +/// ``` +/// +/// Is functionally the same as: +/// +/// ``` +/// # #![allow(unused_imports)] +/// use std::io; +/// use std::io::Read; +/// ``` +/// +/// Using `self` to access an element in the current module: +/// +/// ``` +/// # #![allow(dead_code)] +/// # fn main() {} +/// fn foo() {} +/// fn bar() { +/// self::foo() +/// } +/// ``` +/// +/// `self` as the current receiver for a method allows to omit the parameter +/// type most of the time. With the exception of this particularity, `self` is +/// used much like any other parameter: +/// +/// ``` +/// struct Foo(i32); +/// +/// impl Foo { +/// // No `self`. +/// fn new() -> Self { +/// Self(0) +/// } +/// +/// // Consuming `self`. +/// fn consume(self) -> Self { +/// Self(self.0 + 1) +/// } +/// +/// // Borrowing `self`. +/// fn borrow(&self) -> &i32 { +/// &self.0 +/// } +/// +/// // Borrowing `self` mutably. +/// fn borrow_mut(&mut self) -> &mut i32 { +/// &mut self.0 +/// } +/// } +/// +/// // This method must be called with a `Type::` prefix. +/// let foo = Foo::new(); +/// assert_eq!(foo.0, 0); +/// +/// // Those two calls produces the same result. +/// let foo = Foo::consume(foo); +/// assert_eq!(foo.0, 1); +/// let foo = foo.consume(); +/// assert_eq!(foo.0, 2); +/// +/// // Borrowing is handled automatically with the second syntax. +/// let borrow_1 = Foo::borrow(&foo); +/// let borrow_2 = foo.borrow(); +/// assert_eq!(borrow_1, borrow_2); +/// +/// // Borrowing mutably is handled automatically too with the second syntax. +/// let mut foo = Foo::new(); +/// *Foo::borrow_mut(&mut foo) += 1; +/// assert_eq!(foo.0, 1); +/// *foo.borrow_mut() += 1; +/// assert_eq!(foo.0, 2); +/// ``` +/// +/// Note that this automatic conversion when calling `foo.method()` is not +/// limited to the examples above. See the [Reference] for more information. +/// +/// [`use`]: keyword.use.html +/// [Reference]: ../reference/items/associated-items.html#methods mod self_keyword {} #[doc(keyword = "Self")]