Rust Doc book improvements post-review

src/doc/rustdoc/src/advanced-features.md

@@ -31,4 +31,4 @@ pub struct UnixToken;
 ```
 
 Here, the respective tokens can only be used by dependent crates on their respective platforms, but
-they will both appear in documentation.
+they will both appear in documentation.

src/doc/rustdoc/src/how-to-write-documentation.md

@@ -1,13 +1,13 @@
 # How to write documentation
 
-Good documentation is not natural.  There are opposing forces that make good
-documentation difficult.  It requires expertise in the subject but also
-requires writing to a novice perspective.  Documentation therefore often 
-glazes over implementation detail, or leaves an explain like I'm 5 response.
+Good documentation is not natural.  There are opposing goals that make writing
+good documentation difficult.  It requires expertise in the subject but also
+writing to a novice perspective.  Documentation therefore often glazes over
+implementation detail, or leaves readers with unanswered questions.
 
-There are tenants to Rust documentation that can help guide anyone through
-the process of documenting libraries so everyone has ample opportunity to
-use the code.  
+There are a few tenets to Rust documentation that can help guide anyone through
+the process of documenting libraries so that everyone has an ample opportunity
+to use the code.  
 
 This chapter covers not only how to write documentation but specifically
 how to write **good** documentation.  It is important to be as clear
@@ -18,38 +18,37 @@ then it should be documented.
 ## Getting Started
 
 Documenting a crate should begin with front-page documentation.  As an
-example, [hashbrown] crate level documentation summarizes the role of
-the crate, provides links to explain technical details, and gives the 
-reason why to use the crate.  
+example, the [`hashbrown`] crate level documentation summarizes the role of
+the crate, provides links to explain technical details, and explains why you 
+would want to use the crate.  
 
-After introducing the crate, it is important that within the front-page 
-an example be given how to use the crate in a real world setting.  The
-example benefits from isolating the library's role from the implementation
-details, but doing so without shortcuts also benefits users who may copy
-and paste the example to get started. 
+After introducing the crate, it is important that the front-page gives 
+an example of how to use the crate in a real world setting.  Stick to the
+library's role in the example, but do so without shortcuts to benefit users who
+may copy and paste the example to get started. 
 
-[futures] uses an approach of inline comments to explain line by line
-the complexities of using a future, because often people's first exposure to 
-rust's future is this example.
+[`futures`] uses inline comments to explain line by line
+the complexities of using a [`Future`], because a person's first exposure to 
+rust's [`Future`] may be this example.
 
-[backtrace] usage walks through the whole process, explaining changes made
-to the `Cargo.toml` file, passing command line arguments to the compiler,
-and shows a quick example of backtrace in the wild.  
+The [`backtrace`] documentation walks through the whole process, explaining 
+changes made to the `Cargo.toml` file, passing command line arguments to the
+compiler, and shows a quick example of backtrace in the wild.  
 
 Finally, the front-page can eventually become a comprehensive reference
-how to ues a crate, like the usage found in [regex].  In this front page, all
-the requirements are outlined, the gotchas are taught, then practical examples
-are provided.  The front page goes on to show how to use regular expressions
+how to use a crate, like [`regex`].  In this front page, all
+requirements are outlined, the edge cases shown, and practical examples 
+provided.  The front page goes on to show how to use regular expressions
 then concludes with crate features.
 
-Don't worry about comparing your crate that is just beginning to get
-documentation to something more polished, just start incrementally and put
-in an introduction, example, and features.  Rome wasn't built in a day!
+Don't worry about comparing your crate, which is just beginning.  To get the
+documentation to something more polished, start incrementally and put
+in an introduction, example, and features.  Rome was not built in a day!
 
 The first lines within the `lib.rs` will compose the front-page, and they
 use a different convention than the rest of the rustdocs.  Lines should
-start with `//!` which designate the code to refer to module-level or crate-
-level documentation.  Here's a quick example of the difference:
+start with `//!` which indicate module-level or crate-level documentation.
+Here's a quick example of the difference:
 
 ```rust
 //! Fast and easy queue abstraction.
@@ -65,21 +64,21 @@ level documentation.  Here's a quick example of the difference:
 pub mod easy {
 
     /// Use the abstract function to do this specific thing.
-    pub fn abstract {}
+    pub fn abstract() {}
 
 }
 ```
 
 Ideally, this first line of documentation is a sentence without highly 
-technical details, but very broadly descriptive of where this crate fits
-within the rust ecosystem.  Someone should know if this crate is qualified
-for investigation in their use case by this line.
+technical details, but descriptive of where this crate fits
+within the rust ecosystem.  Users should know whether this crate meets their use
+case after reading this line.
 
 ## Documenting components
 
-Whether documenting modules, structs, functions, or macros, the public
-API of all code should have some documentation, and rarely does anyone
-complain about too much documentation.
+Whether it is modules, structs, functions, or macros: the public
+API of all code should have documentation. Rarely does anyone
+complain about too much documentation!
 
 It is recommended that each item's documentation follows this basic structure:
 
@@ -98,7 +97,7 @@ documentation; while you might think that a code example is trivial,
 the examples are really important because they can help users understand 
 what an item is, how it is used, and for what purpose it exists.
 
-Let's see an example coming from the [standard library] by taking a look at the
+Let us see an example coming from the [standard library] by taking a look at the
 [`std::env::args()`][env::args] function:
 
 ``````text
@@ -133,17 +132,19 @@ for argument in env::args() {
 [`args_os`]: ./fn.args_os.html
 ``````
 
-The first line of description will be reused when describing the component in
-a higher level of the documentation.  For example, the function `std::env::args()`
-above can be found within the [`std::env`] module documentation.
+The first line of description will be reused to describe the component in
+searches and module overviews.  For example, the function `std::env::args()`
+above will be shown on the [`std::env`] module documentation.  Multi-line
+summaries are also possible, however, concise writing is a goal of good
+documentation.
 
 Because the type system does a good job of defining what is passed to a function
-and what is returned from one, there is not a benefit of explicitly writing those
-things into the documentation.  Rustdoc makes sure the links to the types included
-in the signature are linked.
+and what is returned from one, there is not a benefit of explicitly writing it
+into the documentation.  Rustdoc makes sure the links to the types included
+in the function signature are linked.
 
-In the example above, a Panics section explains when the code might abruptly exit
-which can help the reader build guards if required.  A panic section is recommended
+In the example above, a 'Panics' section explains when the code might abruptly exit,
+which can help the reader prevent reaching a panic.  A panic section is recommended
 every time edge cases in your code can be reached if known.
 
 As you can see, it follows the structure detailed above: it starts with a short
@@ -154,17 +155,18 @@ and finally provides a code example.
 
 `rustdoc` is using the [commonmark markdown specification]. You might be
 interested into taking a look at their website to see what's possible to do.
-
-[commonmark quick reference] is a very helpful resource for the majority of
-use cases.
+ - [commonmark quick reference]
+ - [current spec]
 
 
 [backtrace]: https://docs.rs/backtrace/0.3.50/backtrace/
 [commonmark markdown specification]: https://commonmark.org/
 [commonmark quick reference]: https://commonmark.org/help/
 [env::args]: https://doc.rust-lang.org/stable/std/env/fn.args.html
-[futures]: https://docs.rs/futures/0.3.5/futures/
-[hashbrown]: https://docs.rs/hashbrown/0.8.2/hashbrown/
-[regex]: https://docs.rs/regex/1.3.9/regex/
+[`Future`]: https://doc.rust-lang.org/std/future/trait.Future.html 
+[`futures`]: https://docs.rs/futures/0.3.5/futures/
+[`hashbrown`]: https://docs.rs/hashbrown/0.8.2/hashbrown/
+[`regex`]: https://docs.rs/regex/1.3.9/regex/
 [standard library]: https://doc.rust-lang.org/stable/std/index.html
+[current spec]: https://spec.commonmark.org/current/
 [`std::env`]: https://doc.rust-lang.org/stable/std/env/index.html#functions

src/doc/rustdoc/src/references.md

@@ -1,10 +1,7 @@
 # References
 
-There are many great `rustdoc` references out there.  This is a collection of 
-those documentation documents on the internet at the time of writing.  If you
-know of other great resources, please submit a pull request:
-
-[Rust official Github]
+There are many great `rustdoc` references out there.
+If you know of other great resources, please submit a pull request
 
 ## Official 
 
@@ -31,5 +28,4 @@ know of other great resources, please submit a pull request:
 [RFC 1946: Intra Rustdoc Links]: https://rust-lang.github.io/rfcs/1946-intra-rustdoc-links.html
 [RFC (stalled) front page styleguide]: https://github.com/rust-lang/rfcs/pull/1687
 [Rust By Example]: https://doc.rust-lang.org/stable/rust-by-example/meta/doc.html
-[Rust official Github]: https://github.com/rust-lang/rust/pulls
 [Rust Reference]: https://doc.rust-lang.org/stable/reference/comments.html#doc-comments

src/doc/rustdoc/src/what-is-rustdoc.md

@@ -7,22 +7,22 @@ CSS, and JavaScript.
 
 ## Basic usage
 
-Let's give it a try! Let's create a new project with Cargo:
+Let us give it a try! Create a new project with Cargo:
 
 ```bash
 $ cargo new docs
 $ cd docs
 ```
 
-In `src/lib.rs`, you'll find that Cargo has generated some sample code. Delete
+In `src/lib.rs`, Cargo has generated some sample code. Delete
 it and replace it with this:
 
 ```rust
 /// foo is a function
 fn foo() {}
 ```
 
-Let's run `rustdoc` on our code. To do so, we can call it with the path to
+Now, run `rustdoc` on our code. To do so, we can call it with the path to
 our crate root like this:
 
 ```bash
@@ -31,12 +31,12 @@ $ rustdoc src/lib.rs
 
 This will create a new directory, `doc`, with a website inside! In our case,
 the main page is located in `doc/lib/index.html`. If you open that up in
-a web browser, you'll see a page with a search bar, and "Crate lib" at the
+a web browser, you will see a page with a search bar, and "Crate lib" at the
 top, with no contents. 
 
 ## Configuring rustdoc
 
-There's two problems with this: first, why does it
+There are two problems with this: first, why does it
 think that our package is named "lib"? Second, why does it not have any
 contents?
 
@@ -50,7 +50,7 @@ $ rustdoc src/lib.rs --crate-name docs
 
 Now, `doc/docs/index.html` will be generated, and the page says "Crate docs."
 
-For the second issue, it's because our function `foo` is not public; `rustdoc`
+For the second issue, it is because our function `foo` is not public; `rustdoc`
 defaults to generating documentation for only public functions. If we change
 our code...
 
@@ -65,7 +65,7 @@ pub fn foo() {}
 $ rustdoc src/lib.rs --crate-name docs
 ```
 
-We'll have some generated documentation. Open up `doc/docs/index.html` and
+We will have some generated documentation. Open up `doc/docs/index.html` and
 check it out! It should show a link to the `foo` function's page, which
 is located at `doc/docs/fn.foo.html`. On that page, you'll see the "foo is
 a function" we put inside the documentation comment in our crate.
@@ -89,16 +89,16 @@ dependency=<path>/docs/target/debug/deps
 You can see this with `cargo doc --verbose`.
 
 It generates the correct `--crate-name` for us, as well as pointing to
-`src/lib.rs` But what about those other arguments? 
+`src/lib.rs`. But what about those other arguments? 
  - `-o` controls the *o*utput of our docs. Instead of a top-level 
  `doc` directory, notice that Cargo puts generated documentation under 
  `target`. That is the idiomatic place for generated files in Cargo projects.
  - `-L` flag helps rustdoc find the dependencies your code relies on. 
- If our project used dependencies, we'd get documentation for them as well!
+ If our project used dependencies, we would get documentation for them as well!
 
 ## Using standalone Markdown files
 
-`rustdoc` can also generate HTML from standalone Markdown files. Let's
+`rustdoc` can also generate HTML from standalone Markdown files. Let us
 give it a try: create a `README.md` file with these contents:
 
 ````text
@@ -123,7 +123,7 @@ And call `rustdoc` on it:
 $ rustdoc README.md
 ```
 
-You'll find an HTML file in `docs/doc/README.html` generated from its
+You will find an HTML file in `docs/doc/README.html` generated from its
 Markdown contents.
 
 Cargo currently does not understand standalone Markdown files, unfortunately.

src/doc/rustdoc/src/what-to-include.md

@@ -37,38 +37,20 @@ warning: 1 warning emitted
 ```
 
 As a library author, adding the lint `#![deny(missing_docs)]` is a great way to
-ensure the project does not drift away from being documented well, and warn is
-a good way to move towards comprehensive documentation.
+ensure the project does not drift away from being documented well, and
+`#![warn(missing_docs)]` is a good way to move towards comprehensive 
+documentation.  In addition to docs, `#![deny(missing_doc_code_examples)]`
+ensures each function contains a usage example.  In our example above, the
+warning is resolved by adding crate level documentation. 
 
-In our example above, the warning is resolved by adding crate level
-documentation.  The `main` method does not need documentation, but it is 
-present in the output.  If your main method is doing anything special, like
-returning a `Result`, it could use documentation!
-
-```rust
-#![warn(missing_docs)]
-
-//! Run program to print Hello, world.
-
-/// Allows unhandled errors to become program return values
-fn main() -> std::io::Result<()> {
-    print_it();
-    Ok(())
-}
-
-/// Safely prints Hello, world!
-fn print_it() {
-    println!("Hello, world!");
-}
-```
 There are more lints in the upcoming chapter [Lints][rustdoc-lints].
 
 ## Examples
 
 Of course this is contrived to be simple, but part of the power of documentation
 is showing code that is easy to follow, rather than being realistic.  Docs often
-shortcut error handling because often examples become complicated to follow
-with all the necessary set up required for a simple example.
+take shortcuts with error handling because examples can become complicated to
+follow with all the necessary set up required for a simple example.
 
 `Async` is a good example of this.  In order to execute an `async` example, an
 executor needs to be available.  Examples will often shortcut this, and leave
@@ -86,16 +68,16 @@ follow.
 /// ```
 ``````  
 
-When rustdoc wraps that in a main function, it will panic due to the 
-`ParseIntError` trait not implemented.  In order to help both your audience
-and your test suite, this example needs to have additional work performed:
+When rustdoc wraps that in a main function, it will fail to compile because the 
+`ParseIntError` trait is not implemented.  In order to help both your audience
+and your test suite, this example needs some additional code:
 
 ``````rust
 /// Example
 /// ```rust
 /// # main() -> Result<(), std::num::ParseIntError> {
-/// let fourtytwo = "42".parse::<u32>()?;
-/// println!("{} + 10 = {}", fourtytwo, fourtytwo+10);
+/// let fortytwo = "42".parse::<u32>()?;
+/// println!("{} + 10 = {}", fortytwo, fortytwo+10);
 /// #     Ok(())
 /// # }
 /// ```
@@ -108,12 +90,36 @@ upcoming [Documentation tests] chapter.
 ## What to Exclude
 
 Certain parts of your public interface may be included by default in the output
-of rustdoc.  The attribute `#[doc(hidden)]` hides the non-public consumption
-implementation details to facilitate idiomatic Rust.  
+of rustdoc.  The attribute `#[doc(hidden)]` can hide implementation details
+to encourage idiomatic use of the crate.  
+
+For example, an internal `macro!` that makes the crate easier to implement can
+become a footgun for users when it appears in the public documentation.  An
+internal `Error` type may exist, and `impl` details should be hidden, as
+detailed in the [API Guidelines].
+
+## Customizing the output
 
-Good examples are `impl From<Error>` for providing `?` usage, or `impl Display`.
+It is possible to pass a custom css file to `rustdoc` and style the
+documentation.  
 
+```bash
+rustdoc --extend-css custom.css src/lib.rs
+``` 
+
+A good example of using this feature to create a dark theme is documented [on
+this blog].  Just remember, dark theme is already included in the rustdoc output
+by clicking on the paintbrush.  Adding additional options to the themes are
+as easy as creating a custom theme `.css` file and using the following syntax:
+
+```bash
+rustdoc --theme awesome.css src/lib.rs
+```
 
+Here is an example of a new theme, [Ayu].
 
+[Ayu]: https://github.com/rust-lang/rust/blob/master/src/librustdoc/html/static/themes/ayu.css
+[API Guidelines]: https://rust-lang.github.io/api-guidelines/documentation.html#rustdoc-does-not-show-unhelpful-implementation-details-c-hidden
 [Documentation tests]: documentation-tests.md
+[on this blog]: https://blog.guillaume-gomez.fr/articles/2016-09-16+Generating+doc+with+rustdoc+and+a+custom+theme
 [rustdoc-lints]: lints.md