auto merge of #9522 : steveklabnik/rust/doc_std_opts, r=alexcrichton

Added an overview with a 'real' example, as well as toy implementations of all of
the traits.

Closes #9356.

1 files changed, 382 insertions, 2 deletions

diff --git a/src/libstd/ops.rs b/src/libstd/ops.rs
index 1d4d827434b..3418fd939bd 100644
--- a/src/libstd/ops.rs
+++ b/src/libstd/ops.rs
@@ -8,75 +8,455 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-//! Traits for the built-in operators
-
+// So we don't have to document the actual methods on the traits.
 #[allow(missing_doc)];
 
+/*!
+ *
+ * Traits for the built-in operators. Implementing these traits allows you to get
+ * an effect similar to oveloading operators.
+ *
+ * The values for the right hand side of an operator are automatically
+ * borrowed, so `a + b` is sugar for `a.add(&b)`.
+ *
+ * All of these traits are imported by the prelude, so they are available in
+ * every Rust program.
+ *
+ * # Example
+ *
+ * This example creates a `Point` struct that implements `Add` and `Sub`, and then
+ * demonstrates adding and subtracting two `Point`s.
+ *
+ * ```rust
+ * struct Point {
+ *     x: int,
+ *     y: int
+ * }
+ *
+ * impl Add<Point, Point> for Point {
+ *     fn add(&self, other: &Point) -> Point {
+ *         Point {x: self.x + other.x, y: self.y + other.y}
+ *     }
+ * }
+ *
+ * impl Sub<Point, Point> for Point {
+ *     fn sub(&self, other: &Point) -> Point {
+ *         Point {x: self.x - other.x, y: self.y - other.y}
+ *     }
+ * }
+ * fn main() {
+ *     println(format!("{:?}", Point {x: 1, y: 0} + Point {x: 2, y: 3}));
+ *     println(format!("{:?}", Point {x: 1, y: 0} - Point {x: 2, y: 3}));
+ * }
+ * ```
+ *
+ * See the documentation for each trait for a minimum implementation that prints
+ * something to the screen.
+ *
+ */
+
+/**
+ *
+ * The `Drop` trait is used to run some code when a value goes out of scope. This
+ * is sometimes called a 'destructor'.
+ *
+ * # Example
+ *
+ * A trivial implementation of `Drop`. The `drop` method is called when `_x` goes
+ * out of scope, and therefore `main` prints `Dropping!`.
+ *
+ * ```rust
+ * struct HasDrop;
+ *
+ * impl Drop for HasDrop {
+ *   fn drop(&mut self) {
+ *       println("Dropping!");
+ *   }
+ * }
+ *
+ * fn main() {
+ *   let _x = HasDrop;
+ * }
+ * ```
+ */
 #[lang="drop"]
 pub trait Drop {
     fn drop(&mut self);
 }
 
+/**
+ *
+ * The `Add` trait is used to specify the functionality of `+`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `Add`. When `Foo + Foo` happens, it ends up
+ * calling `add`, and therefore, `main` prints `Adding!`.
+ *
+ * ```rust
+ * struct Foo;
+ *
+ * impl Add<Foo, Foo> for Foo {
+ *     fn add(&self, _rhs: &Foo) -> Foo {
+ *       println("Adding!");
+ *       *self
+ *   }
+ * }
+ *
+ * fn main() {
+ *   Foo + Foo;
+ * }
+ * ```
+ */
 #[lang="add"]
 pub trait Add<RHS,Result> {
     fn add(&self, rhs: &RHS) -> Result;
 }
 
+/**
+ *
+ * The `Sub` trait is used to specify the functionality of `-`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `Sub`. When `Foo - Foo` happens, it ends up
+ * calling `sub`, and therefore, `main` prints `Subtracting!`.
+ *
+ * ```rust
+ * struct Foo;
+ *
+ * impl Sub<Foo, Foo> for Foo {
+ *     fn sub(&self, _rhs: &Foo) -> Foo {
+ *         println("Subtracting!");
+ *         *self
+ *     }
+ * }
+ *
+ * fn main() {
+ *     Foo - Foo;
+ * }
+ * ```
+ */
 #[lang="sub"]
 pub trait Sub<RHS,Result> {
     fn sub(&self, rhs: &RHS) -> Result;
 }
 
+/**
+ *
+ * The `Mul` trait is used to specify the functionality of `*`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `Mul`. When `Foo * Foo` happens, it ends up
+ * calling `mul`, and therefore, `main` prints `Multiplying!`.
+ *
+ * ```rust
+ * struct Foo;
+ *
+ * impl Mul<Foo, Foo> for Foo {
+ *     fn mul(&self, _rhs: &Foo) -> Foo {
+ *         println("Multiplying!");
+ *         *self
+ *     }
+ * }
+ *
+ * fn main() {
+ *     Foo * Foo;
+ * }
+ * ```
+ */
 #[lang="mul"]
 pub trait Mul<RHS,Result> {
     fn mul(&self, rhs: &RHS) -> Result;
 }
 
+/**
+ *
+ * The `Div` trait is used to specify the functionality of `/`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `Div`. When `Foo / Foo` happens, it ends up
+ * calling `div`, and therefore, `main` prints `Dividing!`.
+ *
+ * ```
+ * struct Foo;
+ *
+ * impl Div<Foo, Foo> for Foo {
+ *     fn div(&self, _rhs: &Foo) -> Foo {
+ *         println("Dividing!");
+ *         *self
+ *     }
+ * }
+ *
+ * fn main() {
+ *     Foo / Foo;
+ * }
+ * ```
+ */
 #[lang="div"]
 pub trait Div<RHS,Result> {
     fn div(&self, rhs: &RHS) -> Result;
 }
 
+/**
+ *
+ * The `Rem` trait is used to specify the functionality of `%`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `Rem`. When `Foo % Foo` happens, it ends up
+ * calling `rem`, and therefore, `main` prints `Remainder-ing!`.
+ *
+ * ```
+ * struct Foo;
+ *
+ * impl Rem<Foo, Foo> for Foo {
+ *     fn rem(&self, _rhs: &Foo) -> Foo {
+ *         println("Remainder-ing!");
+ *         *self
+ *     }
+ * }
+ *
+ * fn main() {
+ *     Foo % Foo;
+ * }
+ * ```
+ */
 #[lang="rem"]
 pub trait Rem<RHS,Result> {
     fn rem(&self, rhs: &RHS) -> Result;
 }
 
+/**
+ *
+ * The `Neg` trait is used to specify the functionality of unary `-`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `Neg`. When `-Foo` happens, it ends up calling
+ * `neg`, and therefore, `main` prints `Negating!`.
+ *
+ * ```
+ * struct Foo;
+ *
+ * impl Neg<Foo> for Foo {
+ *     fn neg(&self) -> Foo {
+ *         println("Negating!");
+ *         *self
+ *     }
+ * }
+ *
+ * fn main() {
+ *     -Foo;
+ * }
+ * ```
+ */
 #[lang="neg"]
 pub trait Neg<Result> {
     fn neg(&self) -> Result;
 }
 
+/**
+ *
+ * The `Not` trait is used to specify the functionality of unary `!`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `Not`. When `!Foo` happens, it ends up calling
+ * `not`, and therefore, `main` prints `Not-ing!`.
+ *
+ * ```
+ * struct Foo;
+ *
+ * impl Not<Foo> for Foo {
+ *     fn not(&self) -> Foo {
+ *         println("Not-ing!");
+ *         *self
+ *     }
+ * }
+ *
+ * fn main() {
+ *     !Foo;
+ * }
+ * ```
+ */
 #[lang="not"]
 pub trait Not<Result> {
     fn not(&self) -> Result;
 }
 
+/**
+ *
+ * The `BitAnd` trait is used to specify the functionality of `&`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `BitAnd`. When `Foo & Foo` happens, it ends up
+ * calling `bitand`, and therefore, `main` prints `Bitwise And-ing!`.
+ *
+ * ```
+ * struct Foo;
+ *
+ * impl BitAnd<Foo, Foo> for Foo {
+ *     fn bitand(&self, _rhs: &Foo) -> Foo {
+ *         println("Bitwise And-ing!");
+ *         *self
+ *     }
+ * }
+ *
+ * fn main() {
+ *     Foo & Foo;
+ * }
+ * ```
+ */
 #[lang="bitand"]
 pub trait BitAnd<RHS,Result> {
     fn bitand(&self, rhs: &RHS) -> Result;
 }
 
+/**
+ *
+ * The `BitOr` trait is used to specify the functionality of `|`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `BitOr`. When `Foo | Foo` happens, it ends up
+ * calling `bitor`, and therefore, `main` prints `Bitwise Or-ing!`.
+ *
+ * ```
+ * struct Foo;
+ *
+ * impl BitOr<Foo, Foo> for Foo {
+ *     fn bitor(&self, _rhs: &Foo) -> Foo {
+ *         println("Bitwise Or-ing!");
+ *         *self
+ *     }
+ * }
+ *
+ * fn main() {
+ *     Foo | Foo;
+ * }
+ * ```
+ */
 #[lang="bitor"]
 pub trait BitOr<RHS,Result> {
     fn bitor(&self, rhs: &RHS) -> Result;
 }
 
+/**
+ *
+ * The `BitXor` trait is used to specify the functionality of `^`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `BitXor`. When `Foo ^ Foo` happens, it ends up
+ * calling `bixtor`, and therefore, `main` prints `Bitwise Xor-ing!`.
+ *
+ * ```
+ * struct Foo;
+ *
+ * impl BitXor<Foo, Foo> for Foo {
+ *     fn bitxor(&self, _rhs: &Foo) -> Foo {
+ *         println("Bitwise Xor-ing!");
+ *         *self
+ *     }
+ * }
+ *
+ * fn main() {
+ *     Foo ^ Foo;
+ * }
+ * ```
+ */
 #[lang="bitxor"]
 pub trait BitXor<RHS,Result> {
     fn bitxor(&self, rhs: &RHS) -> Result;
 }
 
+/**
+ *
+ * The `Shl` trait is used to specify the functionality of `<<`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `Shl`. When `Foo << Foo` happens, it ends up
+ * calling `shl`, and therefore, `main` prints `Shifting left!`.
+ *
+ * ```
+ * struct Foo;
+ *
+ * impl Shl<Foo, Foo> for Foo {
+ *     fn shl(&self, _rhs: &Foo) -> Foo {
+ *         println("Shifting left!");
+ *         *self
+ *     }
+ * }
+ *
+ * fn main() {
+ *     Foo << Foo;
+ * }
+ * ```
+ */
 #[lang="shl"]
 pub trait Shl<RHS,Result> {
     fn shl(&self, rhs: &RHS) -> Result;
 }
 
+/**
+ *
+ * The `Shr` trait is used to specify the functionality of `>>`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `Shr`. When `Foo >> Foo` happens, it ends up
+ * calling `shr`, and therefore, `main` prints `Shifting right!`.
+ *
+ * ```
+ * struct Foo;
+ *
+ * impl Shr<Foo, Foo> for Foo {
+ *     fn shr(&self, _rhs: &Foo) -> Foo {
+ *         println("Shifting right!");
+ *         *self
+ *     }
+ * }
+ *
+ * fn main() {
+ *     Foo >> Foo;
+ * }
+ * ```
+ */
 #[lang="shr"]
 pub trait Shr<RHS,Result> {
     fn shr(&self, rhs: &RHS) -> Result;
 }
 
+/**
+ *
+ * The `Index` trait is used to specify the functionality of indexing operations
+ * like `arr[idx]`.
+ *
+ * # Example
+ *
+ * A trivial implementation of `Index`. When `Foo[Foo]` happens, it ends up
+ * calling `index`, and therefore, `main` prints `Indexing!`.
+ *
+ * ```
+ * struct Foo;
+ *
+ * impl Index<Foo, Foo> for Foo {
+ *     fn index(&self, _rhs: &Foo) -> Foo {
+ *         println("Indexing!");
+ *         *self
+ *     }
+ * }
+ *
+ * fn main() {
+ *     Foo[Foo];
+ * }
+ * ```
+ */
 #[lang="index"]
 pub trait Index<Index,Result> {
     fn index(&self, index: &Index) -> Result;