version 0.2.3

Fixing links in print.html

.travis.yml

@@ -1,5 +1,14 @@
 language: rust
 
+rust:
+  - stable
+  - beta
+  - nightly
+
+os:
+  - linux
+  - osx
+
 cache: 
   timeout: 360
   cargo: true
@@ -10,16 +19,10 @@ before_cache:
 env:
   global:
     - CRATE_NAME=mdbook
-    - TARGET=x86_64-unknown-linux-gnu
-
-install:
-  - sh ci/install.sh
-  - export PATH=$PATH:$HOME/.cargo/bin
 
 script:
-  - cargo build --all --no-default-features
-  - cargo build --verbose
-  - cargo test --verbose
+  - cargo test --all
+  - cargo test --all --no-default-features
 
 before_deploy:
   - sh ci/before_deploy.sh

CONTRIBUTING.md

@@ -48,6 +48,54 @@ mdBook builds on stable Rust, if you want to build mdBook from source, here are
 
 The resulting binary can be found in `mdBook/target/debug/` under the name `mdBook` or `mdBook.exe`.
 
+### Code Quality
+
+We love code quality and Rust has some excellent tools to assist you with contributions.
+
+#### Formatting Code with rustfmt
+
+Before you make your Pull Request to the project, please run it through the `rustfmt` utility.
+This will ensure we have good quality source code that is better for us all to maintain.
+
+[rustfmt](https://github.com/rust-lang-nursery/rustfmt) has a lot more information on the project.
+The quick guide is
+
+1. Install it
+    ```
+    rustup component add rustfmt
+    ```
+1. You can now run `rustfmt` on a single file simply by...
+    ```
+    rustfmt src/path/to/your/file.rs
+    ```
+   ... or you can format the entire project with
+   ```
+   cargo fmt
+   ```
+   When run through `cargo` it will format all bin and lib files in the current crate.
+
+For more information, such as running it from your favourite editor, please see the `rustfmt` project. [rustfmt](https://github.com/rust-lang-nursery/rustfmt)
+
+
+#### Finding Issues with Clippy
+
+Clippy is a code analyser/linter detecting mistakes, and therfore helps to improve your code.
+Like formatting your code with `rustfmt`, running clippy regularly and before your Pull Request will
+help us maintain awesome code.
+
+The best documentation can be found over at [rust-clippy](https://github.com/rust-lang-nursery/rust-clippy)
+
+1. To install
+    ```
+    rustup component add clippy
+    ```
+2. Running clippy
+    ```
+    cargo clippy
+    ```
+
+Clippy has an ever growing list of checks, that are managed in [lint files](https://rust-lang-nursery.github.io/rust-clippy/master/index.html).
+
 ### Making a pull-request
 
 When you feel comfortable that your changes could be integrated into mdBook, you can create a pull-request on GitHub.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mdbook"
-version = "0.2.0"
+version = "0.2.3"
 authors = [
     "Mathieu David <mathieudavid@mathieudavid.org>", 
     "Michael-F-Bryan <michaelfbryan@gmail.com>",
@@ -17,7 +17,7 @@ exclude = ["book-example/*"]
 [dependencies]
 clap = "2.24"
 chrono = "0.4"
-handlebars = "0.32"
+handlebars = "1.0"
 serde = "1.0"
 serde_derive = "1.0"
 error-chain = "0.12"
@@ -26,7 +26,7 @@ pulldown-cmark = "0.1.2"
 lazy_static = "1.0"
 log = "0.4"
 env_logger = "0.5"
-toml = "0.4"
+toml = "0.4.8"
 memchr = "2.0"
 open = "1.1"
 regex = "1.0.0"

README.md

@@ -145,6 +145,57 @@ explanation, check out the [User Guide].
 
     Delete directory in which generated book is located.
 
+### 3rd Party Plugins
+
+The way a book is loaded and rendered can be configured by the user via third
+party plugins. These plugins are just programs which will be invoked during the
+build process and are split into roughly two categories, *preprocessors* and
+*renderers*.
+
+Preprocessors are used to transform a book before it is sent to a renderer. 
+One example would be to replace all occurrences of 
+`{{#include some_file.ext}}` with the contents of that file. Some existing 
+preprocessors are:
+
+- `index` - a built-in preprocessor (enabled by default) which will transform
+  all `README.md` chapters to `index.md` so `foo/README.md` can be accessed via
+  the url `foo/` when published to a browser
+- `links` - a built-in preprocessor (enabled by default) for expanding the
+  `{{# playpen}}` and `{{# include}}` helpers in a chapter.
+
+Renderers are given the final book so they can do something with it. This is
+typically used for, as the name suggests, rendering the document in a particular
+format, however there's nothing stopping a renderer from doing static analysis
+of a book in order to validate links or run tests. Some existing renderers are:
+
+- `html` - the built-in renderer which will generate a HTML version of the book
+- [`linkcheck`] - a backend which will check that all links are valid
+- [`epub`] - an experimental EPUB generator
+
+> **Note for Developers:** Feel free to send us a PR if you've developed your
+> own plugin and want it mentioned here.
+
+A preprocessor or renderer is enabled by installing the appropriate program and
+then mentioning it in the book's `book.toml` file.
+
+```console
+$ cargo install mdbook-linkcheck
+$ edit book.toml && cat book.toml
+[book]
+title = "My Awesome Book"
+authors = ["Michael-F-Bryan"]
+
+[output.html]
+
+[output.linkcheck]  # enable the "mdbook-linkcheck" renderer
+
+$ mdbook build
+2018-10-20 13:57:51 [INFO] (mdbook::book): Book building has started
+2018-10-20 13:57:51 [INFO] (mdbook::book): Running the html backend
+2018-10-20 13:57:53 [INFO] (mdbook::book): Running the linkcheck backend
+```
+
+For more information on the plugin system, consult the [User Guide].
 
 ### As a library
 
@@ -189,3 +240,5 @@ All the code in this repository is released under the ***Mozilla Public License
 [Rust]: https://www.rust-lang.org/
 [CLI docs]: http://rust-lang-nursery.github.io/mdBook/cli/init.html
 [master-docs]: http://rust-lang-nursery.github.io/mdBook/mdbook/
+[`linkcheck`]: https://crates.io/crates/mdbook-linkcheck
+[`epub`]: https://crates.io/crates/mdbook-epub

appveyor.yml

@@ -36,12 +36,12 @@ build: false
 
 # Equivalent to Travis' `script` phase
 test_script:
-  - cargo build --verbose
-  - cargo test --verbose
+  - cargo test --all
+  - cargo test --all --no-default-features
 
 before_deploy:
   # Generate artifacts for release
-  - cargo build --release
+  - cargo rustc --bin mdbook --release -- -C lto
   - mkdir staging
   - copy target\release\mdbook.exe staging
   - cd staging

book-example/src/README.md

@@ -1,15 +1,25 @@
 # mdBook
 
-**mdBook** is a command line tool and Rust crate to create books using Markdown files. It's very similar to Gitbook but written in [Rust](http://www.rust-lang.org).
+**mdBook** is a command line tool and Rust crate to create books using Markdown
+files. It's very similar to Gitbook but written in
+[Rust](http://www.rust-lang.org).
 
-What you are reading serves as an example of the output of mdBook and at the same time as a high-level documentation.
+What you are reading serves as an example of the output of mdBook and at the
+same time as a high-level documentation.
 
-mdBook is free and open source, you can find the source code on [Github](https://github.com/rust-lang-nursery/mdBook). Issues and feature requests can be posted on the [Github Issue tracker](https://github.com/rust-lang-nursery/mdBook/issues).
+mdBook is free and open source, you can find the source code on
+[GitHub](https://github.com/rust-lang-nursery/mdBook). Issues and feature
+requests can be posted on the [GitHub issue
+tracker](https://github.com/rust-lang-nursery/mdBook/issues).
 
 ## API docs
 
-Alongside this book you can also read the [API docs](https://docs.rs/mdbook/*/mdbook/) generated by Rustdoc if you would like to use mdBook as a crate or write a new renderer and need a more low-level overview.
+Alongside this book you can also read the [API
+docs](https://docs.rs/mdbook/*/mdbook/) generated by Rustdoc if you would like
+to use mdBook as a crate or write a new renderer and need a more low-level
+overview.
 
 ## License
 
-mdBook, all the source code, is released under the [Mozilla Public License v2.0](https://www.mozilla.org/MPL/2.0/)
+mdBook, all the source code, is released under the [Mozilla Public License
+v2.0](https://www.mozilla.org/MPL/2.0/).

book-example/src/cli/README.md

@@ -1,30 +1,49 @@
 # Command Line Tool
 
-mdBook can be used either as a command line tool or a [Rust crate](https://crates.io/crates/mdbook).
-Let's focus on the command line tool capabilities first.
+mdBook can be used either as a command line tool or a [Rust
+crate](https://crates.io/crates/mdbook). Let's focus on the command line tool
+capabilities first.
 
-## Install
+## Install From Binaries
+
+Precompiled binaries are provided for major platforms on a best-effort basis.
+Visit [the releases page](https://github.com/rust-lang-nursery/mdBook/releases)
+to download the appropriate version for your platform.
+
+## Install From Source
+
+mdBook can also be installed from source
 
 ### Pre-requisite
 
-mdBook is written in **[Rust](https://www.rust-lang.org/)** and therefore needs to be compiled with **Cargo**, because we don't yet offer ready-to-go binaries. If you haven't already installed Rust, please go ahead and [install it](https://www.rust-lang.org/downloads.html) now.
+mdBook is written in **[Rust](https://www.rust-lang.org/)** and therefore needs
+to be compiled with **Cargo**. If you haven't already installed Rust, please go
+ahead and [install it](https://www.rust-lang.org/tools/install) now.
 
 ### Install Crates.io version
 
-Installing mdBook is relatively easy if you already have Rust and Cargo installed. You just have to type this snippet in your terminal:
+Installing mdBook is relatively easy if you already have Rust and Cargo
+installed. You just have to type this snippet in your terminal:
 
 ```bash
 cargo install mdbook
 ```
 
-This will fetch the source code from [Crates.io](https://crates.io/) and compile it. You will have to add Cargo's `bin` directory to your `PATH`.
+This will fetch the source code for the latest release from
+[Crates.io](https://crates.io/) and compile it. You will have to add Cargo's
+`bin` directory to your `PATH`.
 
-Run `mdbook help` in your terminal to verify if it works. Congratulations, you have installed mdBook!
+Run `mdbook help` in your terminal to verify if it works. Congratulations, you
+have installed mdBook!
 
 
 ### Install Git version
 
-The **[git version](https://github.com/rust-lang-nursery/mdBook)** contains all the latest bug-fixes and features, that will be released in the next version on **Crates.io**, if you can't wait until the next release. You can build the git version yourself. Open your terminal and navigate to the directory of you choice. We need to clone the git repository and then build it with Cargo.
+The **[git version](https://github.com/rust-lang-nursery/mdBook)** contains all
+the latest bug-fixes and features, that will be released in the next version on
+**Crates.io**, if you can't wait until the next release. You can build the git
+version yourself. Open your terminal and navigate to the directory of you
+choice. We need to clone the git repository and then build it with Cargo.
 
 ```bash
 git clone --depth=1 https://github.com/rust-lang-nursery/mdBook.git
@@ -32,4 +51,5 @@ cd mdBook
 cargo build --release
 ```
 
-The executable `mdbook` will be in the `./target/release` folder, this should be added to the path.
+The executable `mdbook` will be in the `./target/release` folder, this should be
+added to the path.

book-example/src/cli/build.md

@@ -6,8 +6,8 @@ The build command is used to render your book:
 mdbook build
 ```
 
-It will try to parse your `SUMMARY.md` file to understand the structure of your book
-and fetch the corresponding files.
+It will try to parse your `SUMMARY.md` file to understand the structure of your
+book and fetch the corresponding files.
 
 The rendered output will maintain the same directory structure as the source for
 convenience. Large books will therefore remain structured when rendered.
@@ -28,11 +28,12 @@ your default web browser after building it.
 
 #### --dest-dir
 
-The `--dest-dir` (`-d`) option allows you to change the output directory for
-the book. If not specified it will default to the value of the
-`build.build-dir` key in `book.toml`, or to `./book` relative to the book's
-root directory.
+The `--dest-dir` (`-d`) option allows you to change the output directory for the
+book. Relative paths are interpreted relative to the book's root directory. If
+not specified it will default to the value of the `build.build-dir` key in
+`book.toml`, or to `./book`.
 
 -------------------
 
-***Note:*** *Make sure to run the build command in the root directory and not in the source directory*
+***Note:*** *Make sure to run the build command in the root directory and not in
+the source directory*

book-example/src/cli/clean.md

@@ -19,9 +19,9 @@ mdbook clean path/to/book
 #### --dest-dir
 
 The `--dest-dir` (`-d`) option allows you to override the book's output
-directory, which will be deleted by this command. If not specified it
-will default to the value of the `build.build-dir` key in `book.toml`, or to
-`./book` relative to the book's root directory.
+directory, which will be deleted by this command. Relative paths are interpreted
+relative to the book's root directory. If not specified it will default to the
+value of the `build.build-dir` key in `book.toml`, or to `./book`.
 
 ```bash
 mdbook clean --dest-dir=path/to/book

book-example/src/cli/init.md

@@ -1,7 +1,7 @@
 # The init command
 
-There is some minimal boilerplate that is the same for every new book. It's for this purpose
-that mdBook includes an `init` command.
+There is some minimal boilerplate that is the same for every new book. It's for
+this purpose that mdBook includes an `init` command.
 
 The `init` command is used like this:
 
@@ -9,7 +9,8 @@ The `init` command is used like this:
 mdbook init
 ```
 
-When using the `init` command for the first time, a couple of files will be set up for you:
+When using the `init` command for the first time, a couple of files will be set
+up for you:
 ```bash
 book-test/
 ├── book
@@ -18,25 +19,27 @@ book-test/
     └── SUMMARY.md
 ```
 
-- The `src` directory is were you write your book in markdown. It contains all the source files,
-configuration files, etc.
+- The `src` directory is were you write your book in markdown. It contains all
+  the source files, configuration files, etc.
 
-- The `book` directory is where your book is rendered. All the output is ready to be uploaded
-to a server to be seen by your audience.
+- The `book` directory is where your book is rendered. All the output is ready
+  to be uploaded to a server to be seen by your audience.
 
-- The `SUMMARY.md` file is the most important file, it's the skeleton of your book and is
-discussed in more detail [in another chapter](../format/summary.md)
+- The `SUMMARY.md` file is the most important file, it's the skeleton of your
+  book and is discussed in more detail [in another
+  chapter](../format/summary.md)
 
 #### Tip: Generate chapters from SUMMARY.md
 
-When a `SUMMARY.md` file already exists, the `init` command will first parse it and generate the
-missing files according to the paths used in the `SUMMARY.md`. This allows you to think and create
-the whole structure of your book and then let mdBook generate it for you.
+When a `SUMMARY.md` file already exists, the `init` command will first parse it
+and generate the missing files according to the paths used in the `SUMMARY.md`.
+This allows you to think and create the whole structure of your book and then
+let mdBook generate it for you.
 
 #### Specify a directory
 
-The `init` command can take a directory as an argument to use as the book's
-root instead of the current working directory.
+The `init` command can take a directory as an argument to use as the book's root
+instead of the current working directory.
 
 ```bash
 mdbook init path/to/book
@@ -44,8 +47,8 @@ mdbook init path/to/book
 
 #### --theme
 
-When you use the `--theme` flag, the default theme will be copied into a directory
-called `theme` in your source directory so that you can modify it.
+When you use the `--theme` flag, the default theme will be copied into a
+directory called `theme` in your source directory so that you can modify it.
 
-The theme is selectively overwritten, this means that if you don't want to overwrite a
-specific file, just delete it and the default file will be used.
+The theme is selectively overwritten, this means that if you don't want to
+overwrite a specific file, just delete it and the default file will be used.

book-example/src/cli/serve.md

@@ -1,9 +1,12 @@
 # The serve command
 
 The serve command is used to preview a book by serving it over HTTP at
-`localhost:3000` by default. Additionally it watches the book's directory
-for changes, rebuilding the book and refreshing clients for each change.
-A websocket connection is used to trigger the client-side refresh.
+`localhost:3000` by default. Additionally it watches the book's directory for
+changes, rebuilding the book and refreshing clients for each change. A websocket
+connection is used to trigger the client-side refresh.
+
+***Note:*** *The `serve` command is for testing a book's HTML output, and is not
+intended to be a complete HTTP server for a website.*
 
 #### Specify a directory
 
@@ -20,8 +23,8 @@ mdbook serve path/to/book
 to listen on, and the hostname for the browser to connect to for WebSockets.
 
 For example: suppose you have an nginx server for SSL termination which has a
-public address of 192.168.1.100 on port 80 and proxied that to 127.0.0.1 on
-port 8000. To run use the nginx proxy do:
+public address of 192.168.1.100 on port 80 and proxied that to 127.0.0.1 on port
+8000\. To run use the nginx proxy do:
 
 ```bash
 mdbook serve path/to/book -p 8000 -n 127.0.0.1 --websocket-hostname 192.168.1.100
@@ -34,17 +37,12 @@ configured.
 
 #### --open
 
-When you use the `--open` (`-o`) flag, mdbook will open the book in your
-your default web browser after starting the server.
+When you use the `--open` (`-o`) flag, mdbook will open the book in your your
+default web browser after starting the server.
 
 #### --dest-dir
 
-The `--dest-dir` (`-d`) option allows you to change the output directory for
-the book. If not specified it will default to the value of the
-`build.build-dir` key in `book.toml`, or to `./book` relative to the book's
-root directory.
-
------
-
-***Note:*** *The `serve` command is for testing, and is not intended
-to be a complete HTTP server for a website.*
+The `--dest-dir` (`-d`) option allows you to change the output directory for the
+book. Relative paths are interpreted relative to the book's root directory. If
+not specified it will default to the value of the `build.build-dir` key in
+`book.toml`, or to `./book`.

book-example/src/cli/test.md

@@ -5,9 +5,9 @@ When writing a book, you sometimes need to automate some tests. For example,
 of code examples that could get outdated. Therefore it is very important for
 them to be able to automatically test these code examples.
 
-mdBook supports a `test` command that will run all available tests in a book.
-At the moment, only rustdoc tests are supported, but this may be expanded upon
-in the future.
+mdBook supports a `test` command that will run all available tests in a book. At
+the moment, only rustdoc tests are supported, but this may be expanded upon in
+the future.
 
 #### Disable tests on a code block
 
@@ -31,8 +31,8 @@ rustdoc *does* test code blocks which have no language specified:
 
 #### Specify a directory
 
-The `test` command can take a directory as an argument to use as the book's
-root instead of the current working directory.
+The `test` command can take a directory as an argument to use as the book's root
+instead of the current working directory.
 
 ```bash
 mdbook test path/to/book
@@ -47,7 +47,7 @@ comma-delimited list (`-L foo,bar`).
 
 #### --dest-dir
 
-The `--dest-dir` (`-d`) option allows you to change the output directory for
-the book. If not specified it will default to the value of the
-`build.build-dir` key in `book.toml`, or to `./book` relative to the book's
-root directory.
+The `--dest-dir` (`-d`) option allows you to change the output directory for the
+book. Relative paths are interpreted relative to the book's root directory. If
+not specified it will default to the value of the `build.build-dir` key in
+`book.toml`, or to `./book`.

book-example/src/cli/watch.md

@@ -2,8 +2,8 @@
 
 The `watch` command is useful when you want your book to be rendered on every
 file change. You could repeatedly issue `mdbook build` every time a file is
-changed. But using `mdbook watch` once will watch your files and will trigger
-a build automatically whenever you modify a file.
+changed. But using `mdbook watch` once will watch your files and will trigger a
+build automatically whenever you modify a file.
 
 #### Specify a directory
 
@@ -21,7 +21,7 @@ your default web browser.
 
 #### --dest-dir
 
-The `--dest-dir` (`-d`) option allows you to change the output directory for
-the book. If not specified it will default to the value of the
-`build.build-dir` key in `book.toml`, or to `./book` relative to the book's
-root directory.
+The `--dest-dir` (`-d`) option allows you to change the output directory for the
+book. Relative paths are interpreted relative to the book's root directory. If
+not specified it will default to the value of the `build.build-dir` key in
+`book.toml`, or to `./book`.

book-example/src/continuous-integration.md

@@ -26,7 +26,7 @@ before_script:
   - cargo install-update -a
 
 script:
-  - cd path/to/mybook && mdbook build && mdbook test
+  - mdbook build path/to/mybook && mdbook test path/to/mybook
 ```
 
 ## Deploying Your Book to GitHub Pages
@@ -34,9 +34,13 @@ script:
 Following these instructions will result in your book being published to GitHub
 pages after a successful CI run on your repository's `master` branch.
 
-First, create a new GitHub "Personal Access Token" with the "public_repo" permissions (or "repo" for private repositories). Go to your repository's Travis CI settings page and add an environment variable named `GITHUB_TOKEN` that is marked secure and *not* shown in the logs.
+First, create a new GitHub "Personal Access Token" with the "public_repo"
+permissions (or "repo" for private repositories). Go to your repository's Travis
+CI settings page and add an environment variable named `GITHUB_TOKEN` that is
+marked secure and *not* shown in the logs.
 
-Then, append this snippet to your `.travis.yml` and update the path to the `book` directory:
+Then, append this snippet to your `.travis.yml` and update the path to the
+`book` directory:
 
 ```yaml
 deploy:

book-example/src/for_developers/README.md

@@ -1,12 +1,12 @@
 # For Developers
 
-While `mdbook` is mainly used as a command line tool, you can also import the 
+While `mdbook` is mainly used as a command line tool, you can also import the
 underlying library directly and use that to manage a book. It also has a fairly
-flexible plugin mechanism, allowing you to create your own custom tooling and 
+flexible plugin mechanism, allowing you to create your own custom tooling and
 consumers (often referred to as *backends*) if you need to do some analysis of
 the book or render it in a different format.
 
-The *For Developers* chapters are here to show you the more advanced usage of 
+The *For Developers* chapters are here to show you the more advanced usage of
 `mdbook`.
 
 The two main ways a developer can hook into the book's build process is via,
@@ -32,15 +32,15 @@ The process of rendering a book project goes through several steps.
 
 The `mdbook` binary is just a wrapper around the `mdbook` crate, exposing its
 functionality as a command-line program. As such it is quite easy to create your
-own programs which use `mdbook` internally, adding your own functionality (e.g. 
+own programs which use `mdbook` internally, adding your own functionality (e.g.
 a custom preprocessor) or tweaking the build process.
 
 The easiest way to find out how to use the `mdbook` crate is by looking at the
-[API Docs]. The top level documentation explains how one would use the 
+[API Docs]. The top level documentation explains how one would use the
 [`MDBook`] type to load and build a book, while the [config] module gives a good
 explanation on the configuration system.
 
 
 [`MDBook`]: http://rust-lang-nursery.github.io/mdBook/mdbook/book/struct.MDBook.html
-[API Docs]: http://rust-lang-nursery.github.io/mdBook/mdbook/
+[API Docs]: https://docs.rs/mdbook/*/mdbook/
 [config]: file:///home/michael/Documents/forks/mdBook/target/doc/mdbook/config/index.html

book-example/src/for_developers/backends.md

@@ -1,11 +1,11 @@
 # Alternate Backends
 
-A "backend" is simply a program which `mdbook` will invoke during the book 
+A "backend" is simply a program which `mdbook` will invoke during the book
 rendering process. This program is passed a JSON representation of the book and
-configuration information via `stdin`. Once the backend receives this 
+configuration information via `stdin`. Once the backend receives this
 information it is free to do whatever it wants.
 
-There are already several alternate backends on GitHub which can be used as a 
+There are already several alternate backends on GitHub which can be used as a
 rough example of how this is accomplished in practice.
 
 - [mdbook-linkcheck] - a simple program for verifying the book doesn't contain
@@ -21,7 +21,7 @@ no reason why it couldn't be accomplished using something like Python or Ruby.
 
 ## Setting Up
 
-First you'll want to create a new binary program and add `mdbook` as a 
+First you'll want to create a new binary program and add `mdbook` as a
 dependency.
 
 ```
@@ -30,8 +30,8 @@ $ cd mdbook-wordcount
 $ cargo add mdbook
 ```
 
-When our `mdbook-wordcount` plugin is invoked, `mdbook` will send it a JSON 
-version of [`RenderContext`] via our plugin's `stdin`. For convenience, there's 
+When our `mdbook-wordcount` plugin is invoked, `mdbook` will send it a JSON
+version of [`RenderContext`] via our plugin's `stdin`. For convenience, there's
 a [`RenderContext::from_json()`] constructor which will load a `RenderContext`.
 
 This is all the boilerplate necessary for our backend to load the book.
@@ -49,9 +49,9 @@ fn main() {
 }
 ```
 
-> **Note:** The `RenderContext` contains a `version` field. This lets backends 
+> **Note:** The `RenderContext` contains a `version` field. This lets backends
   figure out whether they are compatible with the version of `mdbook` it's being
-  called by. This `version` comes directly from the corresponding field in 
+  called by. This `version` comes directly from the corresponding field in
   `mdbook`'s `Cargo.toml`. 
   
   It is recommended that backends use the [`semver`] crate to inspect this field
@@ -60,7 +60,7 @@ fn main() {
 
 ## Inspecting the Book
 
-Now our backend has a copy of the book, lets count how many words are in each 
+Now our backend has a copy of the book, lets count how many words are in each
 chapter!
 
 Because the `RenderContext` contains a [`Book`] field (`book`), and a `Book` has
@@ -89,8 +89,8 @@ fn count_words(ch: &Chapter) -> usize {
 
 ## Enabling the Backend
 
-Now we've got the basics running, we want to actually use it. First, install
-the program.
+Now we've got the basics running, we want to actually use it. First, install the
+program.
 
 ```
 $ cargo install
@@ -110,15 +110,14 @@ Then `cd` to the particular book you'd like to count the words of and update its
 + [output.wordcount]
 ```
 
-When it loads a book into memory, `mdbook` will inspect your `book.toml` file 
-to try and figure out which backends to use by looking for all `output.*`
-tables. If none are provided it'll fall back to using the default HTML
-renderer. 
+When it loads a book into memory, `mdbook` will inspect your `book.toml` file to
+try and figure out which backends to use by looking for all `output.*` tables.
+If none are provided it'll fall back to using the default HTML renderer. 
 
-Notably, this means if you want to add your own custom backend you'll also
-need to make sure to add the HTML backend, even if its table just stays empty.
+Notably, this means if you want to add your own custom backend you'll also need
+to make sure to add the HTML backend, even if its table just stays empty.
 
-Now you just need to build your book like normal, and everything should *Just 
+Now you just need to build your book like normal, and everything should *Just
 Work*.
 
 ```
@@ -145,11 +144,11 @@ Alternate Backends: 710
 Contributors: 85
 ```
 
-The reason we didn't need to specify the full name/path of our `wordcount` 
-backend is because `mdbook` will try to *infer* the program's name via 
-convention. The executable for the `foo` backend is typically called 
+The reason we didn't need to specify the full name/path of our `wordcount`
+backend is because `mdbook` will try to *infer* the program's name via
+convention. The executable for the `foo` backend is typically called
 `mdbook-foo`, with an associated `[output.foo]` entry in the `book.toml`. To
-explicitly tell `mdbook` what command to invoke (it may require command-line 
+explicitly tell `mdbook` what command to invoke (it may require command-line
 arguments or be an interpreted script), you can use the `command` field.
 
 ```diff
@@ -168,16 +167,16 @@ arguments or be an interpreted script), you can use the `command` field.
 ## Configuration
 
 Now imagine you don't want to count the number of words on a particular chapter
-(it might be generated text/code, etc). The canonical way to do this is via
-the usual `book.toml` configuration file by adding items to your `[output.foo]` 
+(it might be generated text/code, etc). The canonical way to do this is via the
+usual `book.toml` configuration file by adding items to your `[output.foo]`
 table. 
 
 The `Config` can be treated roughly as a nested hashmap which lets you call
 methods like `get()` to access the config's contents, with a
-`get_deserialized()` convenience method for retrieving a value and
-automatically deserializing to some arbitrary type `T`.
+`get_deserialized()` convenience method for retrieving a value and automatically
+deserializing to some arbitrary type `T`.
 
-To implement this, we'll create our own serializable `WordcountConfig` struct 
+To implement this, we'll create our own serializable `WordcountConfig` struct
 which will encapsulate all configuration for this backend.
 
 First add `serde` and `serde_derive` to your `Cargo.toml`,
@@ -229,7 +228,7 @@ and then add a check to make sure we skip ignored chapters.
 
 ## Output and Signalling Failure
 
-While it's nice to print word counts to the terminal when a book is built, it 
+While it's nice to print word counts to the terminal when a book is built, it
 might also be a good idea to output them to a file somewhere. `mdbook` tells a
 backend where it should place any generated output via the `destination` field
 in [`RenderContext`].
@@ -264,7 +263,7 @@ in [`RenderContext`].
 > so it's always a good idea to create it with `fs::create_dir_all()`.
 
 There's always the possibility that an error will occur while processing a book
-(just look at all the `unwrap()`'s we've written already), so `mdbook` will 
+(just look at all the `unwrap()`'s we've written already), so `mdbook` will
 interpret a non-zero exit code as a rendering failure.
 
 For example, if we wanted to make sure all chapters have an *even* number of
@@ -315,27 +314,27 @@ init: 283
 init has an odd number of words!
 2018-01-16 21:21:39 [ERROR] (mdbook::renderer): Renderer exited with non-zero return code.
 2018-01-16 21:21:39 [ERROR] (mdbook::utils): Error: Rendering failed
-2018-01-16 21:21:39 [ERROR] (mdbook::utils): 	Caused By: The "mdbook-wordcount" renderer failed
+2018-01-16 21:21:39 [ERROR] (mdbook::utils):    Caused By: The "mdbook-wordcount" renderer failed
 ```
 
 As you've probably already noticed, output from the plugin's subprocess is
-immediately passed through to the user. It is encouraged for plugins to
-follow the "rule of silence" and only generate output when necessary (e.g. an
-error in generation or a warning).
+immediately passed through to the user. It is encouraged for plugins to follow
+the "rule of silence" and only generate output when necessary (e.g. an error in
+generation or a warning).
 
-All environment variables are passed through to the backend, allowing you to
-use the usual `RUST_LOG` to control logging verbosity.
+All environment variables are passed through to the backend, allowing you to use
+the usual `RUST_LOG` to control logging verbosity.
 
 
 ## Wrapping Up
 
 Although contrived, hopefully this example was enough to show how you'd create
-an alternate backend for `mdbook`. If you feel it's missing something, don't 
+an alternate backend for `mdbook`. If you feel it's missing something, don't
 hesitate to create an issue in the [issue tracker] so we can improve the user
 guide.
 
 The existing backends mentioned towards the start of this chapter should serve
-as a good example of how it's done in real life, so feel free to skim through 
+as a good example of how it's done in real life, so feel free to skim through
 the source code or ask questions.
 
 
@@ -348,5 +347,5 @@ the source code or ask questions.
 [`semver`]: https://crates.io/crates/semver
 [`Book`]: http://rust-lang-nursery.github.io/mdBook/mdbook/book/struct.Book.html
 [`Book::iter()`]: http://rust-lang-nursery.github.io/mdBook/mdbook/book/struct.Book.html#method.iter
-[`Config`]: http://rust-lang-nursery.github.io/mdBook/mdbook/config/struct.Config.html 
+[`Config`]: http://rust-lang-nursery.github.io/mdBook/mdbook/config/struct.Config.html
 [issue tracker]: https://github.com/rust-lang-nursery/mdBook/issues

book-example/src/for_developers/preprocessors.md

@@ -11,64 +11,79 @@ the book. Possible use cases are:
   mathjax equivalents
 
 
-## Implementing a Preprocessor
+## Hooking Into MDBook
 
-A preprocessor is represented by the `Preprocessor` trait.
+MDBook uses a fairly simple mechanism for discovering third party plugins.
+A new table is added to `book.toml` (e.g. `preprocessor.foo` for the `foo`
+preprocessor) and then `mdbook` will try to invoke the `mdbook-foo` program as
+part of the build process.
 
-```rust
-pub trait Preprocessor {
-    fn name(&self) -> &str;
-    fn run(&self, ctx: &PreprocessorContext, book: &mut Book) -> Result<()>;
-}
+While preprocessors can be hard-coded to specify which backend it should be run
+for (e.g. it doesn't make sense for MathJax to be used for non-HTML renderers)
+with the `preprocessor.foo.renderer` key.
+
+```toml
+[book]
+title = "My Book"
+authors = ["Michael-F-Bryan"]
+
+[preprocessor.foo]
+# The command can also be specified manually
+command = "python3 /path/to/foo.py"
+# Only run the `foo` preprocessor for the HTML and EPUB renderer
+renderer = ["html", "epub"]
 ```
 
-Where the `PreprocessorContext` is defined as
+In typical unix style, all inputs to the plugin will be written to `stdin` as
+JSON and `mdbook` will read from `stdout` if it is expecting output.
+
+The easiest way to get started is by creating your own implementation of the
+`Preprocessor` trait (e.g. in `lib.rs`) and then creating a shell binary which
+translates inputs to the correct `Preprocessor` method. For convenience, there
+is [an example no-op preprocessor] in the `examples/` directory which can easily
+be adapted for other preprocessors.
+
+<details>
+<summary>Example no-op preprocessor</summary>
 
 ```rust
-pub struct PreprocessorContext {
-    pub root: PathBuf,
-    pub config: Config,
-}
+// nop-preprocessors.rs
+
+{{#include ../../../examples/nop-preprocessor.rs}}
 ```
+</details>
 
-## A complete Example
+## Hints For Implementing A Preprocessor
 
-The magic happens within the `run(...)` method of the [`Preprocessor`][preprocessor-docs] trait implementation.
+By pulling in `mdbook` as a library, preprocessors can have access to the
+existing infrastructure for dealing with books.
 
-As direct access to the chapters is not possible, you will probably end up iterating
-them using `for_each_mut(...)`:
+For example, a custom preprocessor could use the
+[`CmdPreprocessor::parse_input()`] function to deserialize the JSON written to
+`stdin`. Then each chapter of the `Book` can be mutated in-place via
+[`Book::for_each_mut()`], and then written to `stdout` with the `serde_json`
+crate.
+
+Chapters can be accessed either directly (by recursively iterating over
+chapters) or via the `Book::for_each_mut()` convenience method.
+
+The `chapter.content` is just a string which happens to be markdown. While it's
+entirely possible to use regular expressions or do a manual find & replace,
+you'll probably want to process the input into something more computer-friendly.
+The [`pulldown-cmark`][pc] crate implements a production-quality event-based
+Markdown parser, with the [`pulldown-cmark-to-cmark`][pctc] allowing you to
+translate events back into markdown text.
+
+The following code block shows how to remove all emphasis from markdown,
+without accidentally breaking the document.
 
 ```rust
-book.for_each_mut(|item: &mut BookItem| {
-    if let BookItem::Chapter(ref mut chapter) = *item {
-      eprintln!("{}: processing chapter '{}'", self.name(), chapter.name);
-      res = Some(
-          match Deemphasize::remove_emphasis(&mut num_removed_items, chapter) {
-              Ok(md) => {
-                  chapter.content = md;
-                  Ok(())
-              }
-              Err(err) => Err(err),
-          },
-      );
-  }
-});
-```
-
-The `chapter.content` is just a markdown formatted string, and you will have to
-process it in some way. Even though it's entirely possible to implement some sort of
-manual find & replace operation, if that feels too unsafe you can use [`pulldown-cmark`][pc]
-to parse the string into events and work on them instead.
-
-Finally you can use [`pulldown-cmark-to-cmark`][pctc] to transform these events back to
-a string.
-
-The following code block shows how to remove all emphasis from markdown, and do so
-safely.
-
-```rust
-fn remove_emphasis(num_removed_items: &mut i32, chapter: &mut Chapter) -> Result<String> {
+fn remove_emphasis(
+    num_removed_items: &mut usize,
+    chapter: &mut Chapter,
+) -> Result<String> {
     let mut buf = String::with_capacity(chapter.content.len());
+
     let events = Parser::new(&chapter.content).filter(|e| {
         let should_keep = match *e {
             Event::Start(Tag::Emphasis)
@@ -82,15 +97,19 @@ fn remove_emphasis(num_removed_items: &mut i32, chapter: &mut Chapter) -> Result
         }
         should_keep
     });
-    cmark(events, &mut buf, None)
-        .map(|_| buf)
-        .map_err(|err| Error::from(format!("Markdown serialization failed: {}", err)))
+
+    cmark(events, &mut buf, None).map(|_| buf).map_err(|err| {
+        Error::from(format!("Markdown serialization failed: {}", err))
+    })
 }
 ```
 
 For everything else, have a look [at the complete example][example].
 
-[preprocessor-docs]: https://docs.rs/mdbook/0.1.3/mdbook/preprocess/trait.Preprocessor.html
+[preprocessor-docs]: https://docs.rs/mdbook/latest/mdbook/preprocess/trait.Preprocessor.html
 [pc]: https://crates.io/crates/pulldown-cmark
 [pctc]: https://crates.io/crates/pulldown-cmark-to-cmark
 [example]: https://github.com/rust-lang-nursery/mdBook/blob/master/examples/de-emphasize.rs
+[an example no-op preprocessor]: https://github.com/rust-lang-nursery/mdBook/blob/master/examples/nop-preprocessor.rs
+[`CmdPreprocessor::parse_input()`]: https://docs.rs/mdbook/latest/mdbook/preprocess/trait.Preprocessor.html#method.parse_input
+[`Book::for_each_mut()`]: https://docs.rs/mdbook/latest/mdbook/book/struct.Book.html#method.for_each_mut

book-example/src/format/config.md

@@ -14,6 +14,10 @@ description = "The example book covers examples."
 build-dir = "my-example-book"
 create-missing = false
 
+[preprocess.index]
+
+[preprocess.links]
+
 [output.html]
 additional-css = ["custom.css"]
 
@@ -23,9 +27,9 @@ limit-results = 15
 
 ## Supported configuration options
 
-It is important to note that **any** relative path specified in the in the configuration will
-always be taken relative from the root of the book where the configuration file is located.
-
+It is important to note that **any** relative path specified in the in the
+configuration will always be taken relative from the root of the book where the
+configuration file is located.
 
 ### General metadata
 
@@ -58,13 +62,28 @@ This controls the build process of your book.
   will be created when the book is built (i.e. `create-missing = true`). If this
   is `false` then the build process will instead exit with an error if any files
   do not exist.
-- **preprocess:** Specify which preprocessors to be applied. Default is `["links", "index"]`. To disable default preprocessors, pass an empty array `[]` in.
+- **use-default-preprocessors:** Disable the default preprocessors of (`links` &
+  `index`) by setting this option to `false`.
 
+  If you have the same, and/or other preprocessors declared via their table
+  of configuration, they will run instead.
+
+  - For clarity, with no preprocessor configuration, the default `links` and 
+    `index` will run.
+  - Setting `use-default-preprocessors = false` will disable these
+    default preprocessors from running.
+  - Adding `[preprocessor.links]`, for example, will ensure, regardless of 
+    `use-default-preprocessors` that `links` it will run.
+
+## Configuring Preprocessors
 
 The following preprocessors are available and included by default:
 
-- `links`: Expand the `{{# playpen}}` and `{{# include}}` handlebars helpers in a chapter.
-- `index`: Convert all chapter files named `README.md` into `index.md`. That is to say, all `README.md` would be rendered to an index file `index.html` in the rendered book.
+- `links`: Expand the `{{ #playpen }}` and `{{ #include }}` handlebars
+  helpers in a chapter to include the contents of a file.
+- `index`: Convert all chapter files named `README.md` into `index.md`. That is
+  to say, all `README.md` would be rendered to an index file `index.html` in the
+  rendered book.
 
 
 **book.toml**
@@ -72,36 +91,84 @@ The following preprocessors are available and included by default:
 [build]
 build-dir = "build"
 create-missing = false
-preprocess = ["links", "index"]
+
+[preprocess.links]
+
+[preprocess.index]
 ```
 
+### Custom Preprocessor Configuration
+
+Like renderers, preprocessor will need to be given its own table (e.g.
+`[preprocessor.mathjax]`). In the section, you may then pass extra
+configuration to the preprocessor by adding key-value pairs to the table.
+
+For example
+
+```
+[preprocess.links]
+# set the renderers this preprocessor will run for
+renderers = ["html"]
+some_extra_feature = true
+```
+
+#### Locking a Preprocessor dependency to a renderer
+
+You can explicitly specify that a preprocessor should run for a renderer by
+binding the two together.
+
+```
+[preprocessor.mathjax]
+renderers = ["html"]  # mathjax only makes sense with the HTML renderer
+```
+
+### Provide Your Own Command
+
+By default when you add a `[preprocessor.foo]` table to your `book.toml` file,
+`mdbook` will try to invoke the `mdbook-foo` executa`ble. If you want to use a
+different program name or pass in command-line arguments, this behaviour can
+be overridden by adding a `command` field.
+
+```toml
+[preprocessor.random]
+command = "python random.py"
+```
+
+## Configuring Renderers
+
 ### HTML renderer options
+
 The HTML renderer has a couple of options as well. All the options for the
 renderer need to be specified under the TOML table `[output.html]`.
 
 The following configuration options are available:
 
-- **theme:** mdBook comes with a default theme and all the resource files
-  needed for it. But if this option is set, mdBook will selectively overwrite
-  the theme files with the ones found in the specified folder.
-- **curly-quotes:** Convert straight quotes to curly quotes, except for
-  those that occur in code blocks and code spans. Defaults to `false`.
-- **google-analytics:** If you use Google Analytics, this option lets you
-  enable it by simply specifying your ID in the configuration file.
-- **additional-css:** If you need to slightly change the appearance of your
-  book without overwriting the whole style, you can specify a set of
-  stylesheets that will be loaded after the default ones where you can
-  surgically change the style.
+- **theme:** mdBook comes with a default theme and all the resource files needed
+  for it. But if this option is set, mdBook will selectively overwrite the theme
+  files with the ones found in the specified folder.
+- **default-theme:** The theme color scheme to select by default in the 
+  'Change Theme' dropdown. Defaults to `light`.
+- **curly-quotes:** Convert straight quotes to curly quotes, except for those
+  that occur in code blocks and code spans. Defaults to `false`.
+- **google-analytics:** If you use Google Analytics, this option lets you enable
+  it by simply specifying your ID in the configuration file.
+- **additional-css:** If you need to slightly change the appearance of your book
+  without overwriting the whole style, you can specify a set of stylesheets that
+  will be loaded after the default ones where you can surgically change the
+  style.
 - **additional-js:** If you need to add some behaviour to your book without
-  removing the current behaviour, you can specify a set of JavaScript files
-  that will be loaded alongside the default one.
+  removing the current behaviour, you can specify a set of JavaScript files that
+  will be loaded alongside the default one.
 - **no-section-label:** mdBook by defaults adds section label in table of
-  contents column. For example, "1.", "2.1". Set this option to true to
-  disable those labels. Defaults to `false`.
+  contents column. For example, "1.", "2.1". Set this option to true to disable
+  those labels. Defaults to `false`.
 - **playpen:** A subtable for configuring various playpen settings.
-- **search:** A subtable for configuring the in-browser search
-  functionality. mdBook must be compiled with the `search` feature enabled
-  (on by default).
+- **search:** A subtable for configuring the in-browser search functionality.
+  mdBook must be compiled with the `search` feature enabled (on by default).
+- **git_repository_url:**  A url to the git repository for the book. If provided
+  an icon link will be output in the menu bar of the book.
+- **git_repository_icon:** The FontAwesome icon class to use for the git
+  repository link. Defaults to `fa-github`.
 
 Available configuration options for the `[output.html.playpen]` table:
 
@@ -115,27 +182,27 @@ Available configuration options for the `[output.html.search]` table:
 
 - **enable:** Enables the search feature. Defaults to `true`.
 - **limit-results:** The maximum number of search results. Defaults to `30`.
-- **teaser-word-count:** The number of words used for a search result teaser. 
+- **teaser-word-count:** The number of words used for a search result teaser.
   Defaults to `30`.
-- **use-boolean-and:** Define the logical link between multiple search words. 
-  If true, all search words must appear in each result. Defaults to `true`.
+- **use-boolean-and:** Define the logical link between multiple search words. If
+  true, all search words must appear in each result. Defaults to `true`.
 - **boost-title:** Boost factor for the search result score if a search word
   appears in the header. Defaults to `2`.
-- **boost-hierarchy:** Boost factor for the search result score if a search
-  word appears in the hierarchy. The hierarchy contains all titles of the
-  parent documents and all parent headings. Defaults to `1`.
-- **boost-paragraph:** Boost factor for the search result score if a search 
-  word appears in the text. Defaults to `1`.
-- **expand:** True if search should match longer results e.g. search `micro` 
+- **boost-hierarchy:** Boost factor for the search result score if a search word
+  appears in the hierarchy. The hierarchy contains all titles of the parent
+  documents and all parent headings. Defaults to `1`.
+- **boost-paragraph:** Boost factor for the search result score if a search word
+  appears in the text. Defaults to `1`.
+- **expand:** True if search should match longer results e.g. search `micro`
   should match `microwave`. Defaults to `true`.
 - **heading-split-level:** Search results will link to a section of the document
-  which contains the result. Documents are split into sections by headings
-  this level or less.
-  Defaults to `3`. (`### This is a level 3 heading`)
-- **copy-js:** Copy JavaScript files for the search implementation to the
-  output directory. Defaults to `true`.
+  which contains the result. Documents are split into sections by headings this
+  level or less. Defaults to `3`. (`### This is a level 3 heading`)
+- **copy-js:** Copy JavaScript files for the search implementation to the output
+  directory. Defaults to `true`.
+
+This shows all available HTML output options in the **book.toml**:
 
-This shows all available options in the **book.toml**:
 ```toml
 [book]
 title = "Example book"
@@ -172,6 +239,16 @@ heading-split-level = 3
 copy-js = true
 ```
 
+### Custom Renderers
+
+A custom renderer can be enabled by adding a `[output.foo]` table to your 
+`book.toml`. Similar to [preprocessors](#configuring-preprocessors) this will 
+instruct `mdbook` to pass a representation of the book to `mdbook-foo` for 
+rendering.
+
+Custom renderers will have access to all configuration within their table
+(i.e. anything under `[output.foo]`), and the command to be invoked can be 
+manually specified with the `command` field.
 
 ## Environment Variables
 
@@ -180,10 +257,10 @@ corresponding environment variable. Because many operating systems restrict
 environment variables to be alphanumeric characters or `_`, the configuration
 key needs to be formatted slightly differently to the normal `foo.bar.baz` form.
 
-Variables starting with `MDBOOK_` are used for configuration. The key is
-created by removing the `MDBOOK_` prefix and turning the resulting
-string into `kebab-case`. Double underscores (`__`) separate nested
-keys, while a single underscore (`_`) is replaced with a dash (`-`).
+Variables starting with `MDBOOK_` are used for configuration. The key is created
+by removing the `MDBOOK_` prefix and turning the resulting string into
+`kebab-case`. Double underscores (`__`) separate nested keys, while a single
+underscore (`_`) is replaced with a dash (`-`).
 
 For example:
 
@@ -193,21 +270,21 @@ For example:
 - `MDBOOK_FOO_BAR` -> `foo-bar`
 - `MDBOOK_FOO_bar__baz` -> `foo-bar.baz`
 
-So by setting the `MDBOOK_BOOK__TITLE` environment variable you can
-override the book's title without needing to touch your `book.toml`.
+So by setting the `MDBOOK_BOOK__TITLE` environment variable you can override the
+book's title without needing to touch your `book.toml`.
 
-> **Note:** To facilitate setting more complex config items, the value
-> of an environment variable is first parsed as JSON, falling back to a
-> string if the parse fails.
+> **Note:** To facilitate setting more complex config items, the value of an
+> environment variable is first parsed as JSON, falling back to a string if the
+> parse fails.
 >
-> This means, if you so desired, you could override all book metadata
-> when building the book with something like
+> This means, if you so desired, you could override all book metadata when
+> building the book with something like
 >
 > ```text
 > $ export MDBOOK_BOOK="{'title': 'My Awesome Book', authors: ['Michael-F-Bryan']}"
 > $ mdbook build
 > ```
 
-The latter case may be useful in situations where `mdbook` is invoked
-from a script or CI, where it sometimes isn't possible to update the
-`book.toml` before building.
+The latter case may be useful in situations where `mdbook` is invoked from a
+script or CI, where it sometimes isn't possible to update the `book.toml` before
+building.

book-example/src/format/mathjax.md

@@ -1,29 +1,37 @@
 # MathJax Support
 
-mdBook has optional support for math equations through [MathJax](https://www.mathjax.org/).
+mdBook has optional support for math equations through
+[MathJax](https://www.mathjax.org/).
 
-To enable MathJax, you need to add the `mathjax-support` key to your `book.toml` under the `output.html` section.
+To enable MathJax, you need to add the `mathjax-support` key to your `book.toml`
+under the `output.html` section.
 
 ```toml
 [output.html]
 mathjax-support = true
 ```
 
->**Note:**
-The usual delimiters MathJax uses are not yet supported. You can't currently use `$$ ... $$` as delimiters and the `\[ ... \]` delimiters need an extra backslash to work. Hopefully this limitation will be lifted soon.
+>**Note:** The usual delimiters MathJax uses are not yet supported. You can't
+currently use `$$ ... $$` as delimiters and the `\[ ... \]` delimiters need an
+extra backslash to work. Hopefully this limitation will be lifted soon.
 
->**Note:**
-> When you use double backslashes in MathJax blocks (for example in commands such as `\begin{cases} \frac 1 2 \\ \frac 3 4 \end{cases}`) you need to add _two extra_ backslashes (e.g., `\begin{cases} \frac 1 2 \\\\ \frac 3 4 \end{cases}`).
+>**Note:** When you use double backslashes in MathJax blocks (for example in
+> commands such as `\begin{cases} \frac 1 2 \\ \frac 3 4 \end{cases}`) you need
+> to add _two extra_ backslashes (e.g., `\begin{cases} \frac 1 2 \\\\ \frac 3 4
+> \end{cases}`).
 
 
 ### Inline equations
-Inline equations are delimited by `\\(` and `\\)`. So for example, to render the following inline equation \\( \int x dx = \frac{x^2}{2} + C \\) you would write the following:
+Inline equations are delimited by `\\(` and `\\)`. So for example, to render the
+following inline equation \\( \int x dx = \frac{x^2}{2} + C \\) you would write
+the following:
 ```
 \\( \int x dx = \frac{x^2}{2} + C \\)
 ```
 
 ### Block equations
-Block equations are delimited by `\\[` and `\\]`. To render the following equation
+Block equations are delimited by `\\[` and `\\]`. To render the following
+equation
 
 \\[ \mu = \frac{1}{N} \sum_{i=0} x_i \\]
 

book-example/src/format/mdbook.md

@@ -2,7 +2,8 @@
 
 ## Hiding code lines
 
-There is a feature in mdBook that lets you hide code lines by prepending them with a `#`.
+There is a feature in mdBook that lets you hide code lines by prepending them
+with a `#`.
 
 ```bash
 # fn main() {
@@ -34,7 +35,10 @@ With the following syntax, you can include files into your book:
 
 The path to the file has to be relative from the current source file.
 
-Usually, this command is used for including code snippets and examples. In this case, oftens one would include a specific part of the file e.g. which only contains the relevant lines for the example. We support four different modes of partial includes:
+Usually, this command is used for including code snippets and examples. In this
+case, oftens one would include a specific part of the file e.g. which only
+contains the relevant lines for the example. We support four different modes of
+partial includes:
 
 ```hbs
 \{{#include file.rs:2}}
@@ -43,7 +47,11 @@ Usually, this command is used for including code snippets and examples. In this
 \{{#include file.rs:2:10}}
 ```
 
-The first command only includes the second line from file `file.rs`. The second command includes all lines up to line 10, i.e. the lines from 11 till the end of the file are omitted. The third command includes all lines from line 2, i.e. the first line is omitted. The last command includes the excerpt of `file.rs` consisting of lines 2 to 10.
+The first command only includes the second line from file `file.rs`. The second
+command includes all lines up to line 10, i.e. the lines from 11 till the end of
+the file are omitted. The third command includes all lines from line 2, i.e. the
+first line is omitted. The last command includes the excerpt of `file.rs`
+consisting of lines 2 to 10.
 
 ## Inserting runnable Rust files
 
@@ -55,7 +63,9 @@ With the following syntax, you can insert runnable Rust files into your book:
 
 The path to the Rust file has to be relative from the current source file.
 
-When play is clicked, the code snippet will be sent to the [Rust Playpen] to be compiled and run. The result is sent back and displayed directly underneath the code.
+When play is clicked, the code snippet will be sent to the [Rust Playpen] to be
+compiled and run. The result is sent back and displayed directly underneath the
+code.
 
 Here is what a rendered code snippet looks like:
 

book-example/src/format/summary.md

@@ -1,32 +1,38 @@
 # SUMMARY.md
 
-The summary file is used by mdBook to know what chapters to include,
-in what order they should appear, what their hierarchy is and where the source files are.
-Without this file, there is no book.
+The summary file is used by mdBook to know what chapters to include, in what
+order they should appear, what their hierarchy is and where the source files
+are. Without this file, there is no book.
 
 Even though `SUMMARY.md` is a markdown file, the formatting is very strict to
 allow for easy parsing. Let's see how you should format your `SUMMARY.md` file.
 
 #### Allowed elements
 
-1. ***Title*** It's common practice to begin with a title, generally
-   <code class="language-markdown"># Summary</code>.
-   But it is not mandatory, the parser just ignores it. So you can too
-   if you feel like it.
+1. ***Title*** It's common practice to begin with a title, generally <code
+   class="language-markdown"># Summary</code>. But it is not mandatory, the
+   parser just ignores it. So you can too if you feel like it.
 
-2. ***Prefix Chapter*** Before the main numbered chapters you can add a couple of elements that will not be numbered. This is useful for
-   forewords, introductions, etc. There are however some constraints. You can not nest prefix chapters, they should all be on the root level. And you can not add prefix chapters once you have added numbered chapters.
+2. ***Prefix Chapter*** Before the main numbered chapters you can add a couple
+   of elements that will not be numbered. This is useful for forewords,
+   introductions, etc. There are however some constraints. You can not nest
+   prefix chapters, they should all be on the root level. And you can not add
+   prefix chapters once you have added numbered chapters.
    ```markdown
    [Title of prefix element](relative/path/to/markdown.md)
    ```
 
-3. ***Numbered Chapter*** Numbered chapters are the main content of the book, they will be numbered and can be nested,
-   resulting in a nice hierarchy (chapters, sub-chapters, etc.)
+3. ***Numbered Chapter*** Numbered chapters are the main content of the book,
+   they will be numbered and can be nested, resulting in a nice hierarchy
+   (chapters, sub-chapters, etc.)
    ```markdown
    - [Title of the Chapter](relative/path/to/markdown.md)
    ```
    You can either use `-` or `*` to indicate a numbered chapter.
 
-4. ***Suffix Chapter*** After the numbered chapters you can add a couple of non-numbered chapters. They are the same as prefix chapters but come after the numbered chapters instead of before.
+4. ***Suffix Chapter*** After the numbered chapters you can add a couple of
+   non-numbered chapters. They are the same as prefix chapters but come after
+   the numbered chapters instead of before.
 
-All other elements are unsupported and will be ignored at best or result in an error.
+All other elements are unsupported and will be ignored at best or result in an
+error.

book-example/src/format/theme/README.md

@@ -1,22 +1,34 @@
 # Theme
 
-The default renderer uses a [handlebars](http://handlebarsjs.com/) template to render your markdown files and comes with a default theme
-included in the mdBook binary.
+The default renderer uses a [handlebars](http://handlebarsjs.com/) template to
+render your markdown files and comes with a default theme included in the mdBook
+binary.
 
-The theme is totally customizable, you can selectively replace every file from the theme by your own by adding a
-`theme` directory next to `src` folder in your project root. Create a new file with the name of the file you want to override
+The theme is totally customizable, you can selectively replace every file from
+the theme by your own by adding a `theme` directory next to `src` folder in your
+project root. Create a new file with the name of the file you want to override
 and now that file will be used instead of the default file.
 
 Here are the files you can override:
 
 - ***index.hbs*** is the handlebars template.
-- ***book.css*** is the style used in the output. If you want to change the design of your book, this is probably the file you want to modify. Sometimes in conjunction with `index.hbs` when you want to radically change the layout.
-- ***book.js*** is mostly used to add client side functionality, like hiding / un-hiding the sidebar, changing the theme, ...
-- ***highlight.js*** is the JavaScript that is used to highlight code snippets, you should not need to modify this.  
+- ***book.css*** is the style used in the output. If you want to change the
+  design of your book, this is probably the file you want to modify. Sometimes
+  in conjunction with `index.hbs` when you want to radically change the layout.
+- ***book.js*** is mostly used to add client side functionality, like hiding /
+  un-hiding the sidebar, changing the theme, ...
+- ***highlight.js*** is the JavaScript that is used to highlight code snippets,
+  you should not need to modify this.  
 - ***highlight.css*** is the theme used for the code highlighting
 - ***favicon.png*** the favicon that will be used
 
-Generally, when you want to tweak the theme, you don't need to override all the files. If you only need changes in the stylesheet,
-there is no point in overriding all the other files. Because custom files take precedence over built-in ones, they will not get updated with new fixes / features.
+Generally, when you want to tweak the theme, you don't need to override all the
+files. If you only need changes in the stylesheet, there is no point in
+overriding all the other files. Because custom files take precedence over
+built-in ones, they will not get updated with new fixes / features.
 
-**Note:** When you override a file, it is possible that you break some functionality. Therefore I recommend to use the file from the default theme as template and only add / modify what you need. You can copy the default theme into your source directory automatically by using `mdbook init --theme` just remove the files you don't want to override.
+**Note:** When you override a file, it is possible that you break some
+functionality. Therefore I recommend to use the file from the default theme as
+template and only add / modify what you need. You can copy the default theme
+into your source directory automatically by using `mdbook init --theme` just
+remove the files you don't want to override.

book-example/src/format/theme/editor.md

@@ -1,13 +1,16 @@
 # Editor
 
-In addition to providing runnable code playpens, mdBook optionally allows them to be editable. In order to enable editable code blocks, the following needs to be added to the ***book.toml***:
+In addition to providing runnable code playpens, mdBook optionally allows them
+to be editable. In order to enable editable code blocks, the following needs to
+be added to the ***book.toml***:
 
 ```toml
 [output.html.playpen]
 editable = true
 ```
 
-To make a specific block available for editing, the attribute `editable` needs to be added to it:
+To make a specific block available for editing, the attribute `editable` needs
+to be added to it:
 
 <pre><code class="language-markdown">```rust,editable
 fn main() {
@@ -29,7 +32,8 @@ Note the new `Undo Changes` button in the editable playpens.
 
 ## Customizing the Editor
 
-By default, the editor is the [Ace](https://ace.c9.io/) editor, but, if desired, the functionality may be overriden by providing a different folder:
+By default, the editor is the [Ace](https://ace.c9.io/) editor, but, if desired,
+the functionality may be overriden by providing a different folder:
 
 ```toml
 [output.html.playpen]
@@ -37,4 +41,6 @@ editable = true
 editor = "/path/to/editor"
 ```
 
-Note that for the editor changes to function correctly, the `book.js` inside of the `theme` folder will need to be overriden as it has some couplings with the default Ace editor.
+Note that for the editor changes to function correctly, the `book.js` inside of
+the `theme` folder will need to be overriden as it has some couplings with the
+default Ace editor.

book-example/src/format/theme/index-hbs.md

@@ -1,15 +1,15 @@
 # index.hbs
 
-`index.hbs` is the handlebars template that is used to render the book.
-The markdown files are processed to html and then injected in that template.
+`index.hbs` is the handlebars template that is used to render the book. The
+markdown files are processed to html and then injected in that template.
 
-If you want to change the layout or style of your book, chances are that you will
-have to modify this template a little bit. Here is what you need to know.
+If you want to change the layout or style of your book, chances are that you
+will have to modify this template a little bit. Here is what you need to know.
 
 ## Data
 
-A lot of data is exposed to the handlebars template with the "context".
-In the handlebars template you can access this information by using
+A lot of data is exposed to the handlebars template with the "context". In the
+handlebars template you can access this information by using
 
 ```handlebars
 {{name_of_property}}
@@ -17,25 +17,31 @@ In the handlebars template you can access this information by using
 
 Here is a list of the properties that are exposed:
 
-- ***language*** Language of the book in the form `en`. To use in <code class="language-html">\<html lang="{{ language }}"></code> for example.
-At the moment it is hardcoded.
+- ***language*** Language of the book in the form `en`. To use in <code
+  class="language-html">\<html lang="{{ language }}"></code> for example. At the
+  moment it is hardcoded.
 - ***title*** Title of the book, as specified in `book.toml`
 - ***chapter_title*** Title of the current chapter, as listed in `SUMMARY.md`
 
-- ***path*** Relative path to the original markdown file from the source directory
+- ***path*** Relative path to the original markdown file from the source
+  directory
 - ***content*** This is the rendered markdown.
-- ***path_to_root*** This is a path containing exclusively `../`'s that points to the root of the book from the current file.
-Since the original directory structure is maintained, it is useful to prepend relative links with this `path_to_root`.
+- ***path_to_root*** This is a path containing exclusively `../`'s that points
+  to the root of the book from the current file. Since the original directory
+  structure is maintained, it is useful to prepend relative links with this
+  `path_to_root`.
 
 - ***chapters*** Is an array of dictionaries of the form
   ```json
   {"section": "1.2.1", "name": "name of this chapter", "path": "dir/markdown.md"}
   ```
-  containing all the chapters of the book. It is used for example to construct the table of contents (sidebar).
+  containing all the chapters of the book. It is used for example to construct
+  the table of contents (sidebar).
 
 ## Handlebars Helpers
 
-In addition to the properties you can access, there are some handlebars helpers at your disposal.
+In addition to the properties you can access, there are some handlebars helpers
+at your disposal.
 
 ### 1. toc
 
@@ -87,4 +93,5 @@ In addition to the properties you can access, there are some handlebars helpers
 
 ------
 
-*If you would like other properties or helpers exposed, please [create a new issue](https://github.com/rust-lang-nursery/mdBook/issues)*
+*If you would like other properties or helpers exposed, please [create a new
+issue](https://github.com/rust-lang-nursery/mdBook/issues)*

book-example/src/format/theme/syntax-highlighting.md

@@ -1,6 +1,7 @@
 # Syntax Highlighting
 
-For syntax highlighting I use [Highlight.js](https://highlightjs.org) with a custom theme.
+For syntax highlighting I use [Highlight.js](https://highlightjs.org) with a
+custom theme.
 
 Automatic language detection has been turned off, so you will probably want to
 specify the programming language you use like this
@@ -12,19 +13,23 @@ fn main() {
 ```</code></pre>
 
 ## Custom theme
-Like the rest of the theme, the files used for syntax highlighting can be overridden with your own.
+Like the rest of the theme, the files used for syntax highlighting can be
+overridden with your own.
 
-- ***highlight.js*** normally you shouldn't have to overwrite this file, unless you want to use a more recent version.
+- ***highlight.js*** normally you shouldn't have to overwrite this file, unless
+  you want to use a more recent version.
 - ***highlight.css*** theme used by highlight.js for syntax highlighting.
 
-If you want to use another theme for `highlight.js` download it from their website, or make it yourself,
-rename it to `highlight.css` and put it in `src/theme` (or the equivalent if you changed your source folder)
+If you want to use another theme for `highlight.js` download it from their
+website, or make it yourself, rename it to `highlight.css` and put it in
+`src/theme` (or the equivalent if you changed your source folder)
 
 Now your theme will be used instead of the default theme.
 
 ## Hiding code lines
 
-There is a feature in mdBook that let's you hide code lines by prepending them with a `#`.
+There is a feature in mdBook that lets you hide code lines by prepending them
+with a `#`.
 
 
 ```bash
@@ -47,13 +52,18 @@ Will render as
 # }
 ```
 
-**At the moment, this only works for code examples that are annotated with `rust`. Because it would collide with semantics of some programming languages. In the future, we want to make this configurable through the `book.toml` so that everyone can benefit from it.**
+**At the moment, this only works for code examples that are annotated with
+`rust`. Because it would collide with semantics of some programming languages.
+In the future, we want to make this configurable through the `book.toml` so that
+everyone can benefit from it.**
 
 
 ## Improve default theme
 
-If you think the default theme doesn't look quite right for a specific language, or could be improved.
-Feel free to [submit a new issue](https://github.com/rust-lang-nursery/mdBook/issues) explaining what you have in mind and I will take a look at it.
+If you think the default theme doesn't look quite right for a specific language,
+or could be improved. Feel free to [submit a new
+issue](https://github.com/rust-lang-nursery/mdBook/issues) explaining what you
+have in mind and I will take a look at it.
 
 You could also create a pull-request with the proposed improvements.
 

book-example/src/misc/contributors.md

@@ -1,8 +1,7 @@
 # Contributors
 
-Here is a list of the contributors who have helped improving mdBook. Big shout-out to them!
-
-If you have contributed to mdBook and I forgot to add you, don't hesitate to add yourself to the list. If you are in the list, feel free to add your real name & contact information if you wish.
+Here is a list of the contributors who have helped improving mdBook. Big
+shout-out to them!
 
 - [mdinger](https://github.com/mdinger)
 - Kevin ([kbknapp](https://github.com/kbknapp))
@@ -12,8 +11,10 @@ If you have contributed to mdBook and I forgot to add you, don't hesitate to add
 - [funnkill](https://github.com/funkill)
 - Fu Gangqiang ([FuGangqiang](https://github.com/FuGangqiang))
 - [Michael-F-Bryan](https://github.com/Michael-F-Bryan)
-- [Chris Spiegel](https://github.com/cspiegel)
+- Chris Spiegel ([cspiegel](https://github.com/cspiegel))
 - [projektir](https://github.com/projektir)
 - [Phaiax](https://github.com/Phaiax)
-- [Matt Ickstadt](https://github.com/mattico)
+- Matt Ickstadt ([mattico](https://github.com/mattico))
 - Weihang Lo ([@weihanglo](https://github.com/weihanglo))
+
+If you feel you're missing from this list, feel free to add yourself in a PR.

ci/install.sh

@@ -1,47 +0,0 @@
-set -ex
-
-main() {
-    local target=
-    if [ $TRAVIS_OS_NAME = linux ]; then
-        target=x86_64-unknown-linux-musl
-        sort=sort
-    else
-        target=x86_64-apple-darwin
-        sort=gsort  # for `sort --sort-version`, from brew's coreutils.
-    fi
-
-    # Builds for iOS are done on OSX, but require the specific target to be
-    # installed.
-    case $TARGET in
-        aarch64-apple-ios)
-            rustup target install aarch64-apple-ios
-            ;;
-        armv7-apple-ios)
-            rustup target install armv7-apple-ios
-            ;;
-        armv7s-apple-ios)
-            rustup target install armv7s-apple-ios
-            ;;
-        i386-apple-ios)
-            rustup target install i386-apple-ios
-            ;;
-        x86_64-apple-ios)
-            rustup target install x86_64-apple-ios
-            ;;
-    esac
-
-    # This fetches latest stable release
-    local tag=$(git ls-remote --tags --refs --exit-code https://github.com/japaric/cross \
-                       | cut -d/ -f3 \
-                       | grep -E '^v[0.1.0-9.]+$' \
-                       | $sort --version-sort \
-                       | tail -n1)
-    curl -LSfs https://japaric.github.io/trust/install.sh | \
-        sh -s -- \
-           --force \
-           --git japaric/cross \
-           --tag $tag \
-           --target $target
-}
-
-main

examples/de-emphasize.rs

@@ -1,4 +1,6 @@
-//! This program removes all forms of emphasis from the markdown of the book.
+//! An example preprocessor for removing all forms of emphasis from a markdown
+//! book.
+
 extern crate mdbook;
 extern crate pulldown_cmark;
 extern crate pulldown_cmark_to_cmark;
@@ -6,89 +8,73 @@ extern crate pulldown_cmark_to_cmark;
 use mdbook::book::{Book, BookItem, Chapter};
 use mdbook::errors::{Error, Result};
 use mdbook::preprocess::{Preprocessor, PreprocessorContext};
-use mdbook::MDBook;
 use pulldown_cmark::{Event, Parser, Tag};
 use pulldown_cmark_to_cmark::fmt::cmark;
 
-use std::env::{args, args_os};
-use std::ffi::OsString;
-use std::process;
+const NAME: &str = "md-links-to-html-links";
 
+fn main() {
+    panic!("This example is intended to be part of a library");
+}
+
+#[allow(dead_code)]
 struct Deemphasize;
 
 impl Preprocessor for Deemphasize {
     fn name(&self) -> &str {
-        "md-links-to-html-links"
+        NAME
     }
 
-    fn run(&self, _ctx: &PreprocessorContext, book: &mut Book) -> Result<()> {
+    fn run(&self, _ctx: &PreprocessorContext, mut book: Book) -> Result<Book> {
         eprintln!("Running '{}' preprocessor", self.name());
-        let mut res: Option<_> = None;
         let mut num_removed_items = 0;
-        book.for_each_mut(|item: &mut BookItem| {
-            if let Some(Err(_)) = res {
-                return;
-            }
-            if let BookItem::Chapter(ref mut chapter) = *item {
-                eprintln!("{}: processing chapter '{}'", self.name(), chapter.name);
-                res = Some(
-                    match Deemphasize::remove_emphasis(&mut num_removed_items, chapter) {
-                        Ok(md) => {
-                            chapter.content = md;
-                            Ok(())
-                        }
-                        Err(err) => Err(err),
-                    },
-                );
-            }
-        });
+
+        process(&mut book.sections, &mut num_removed_items)?;
+
         eprintln!(
             "{}: removed {} events from markdown stream.",
             self.name(),
             num_removed_items
         );
-        match res {
-            Some(res) => res,
-            None => Ok(()),
+
+        Ok(book)
+    }
+}
+
+fn process<'a, I>(items: I, num_removed_items: &mut usize) -> Result<()>
+where
+    I: IntoIterator<Item = &'a mut BookItem> + 'a,
+{
+    for item in items {
+        if let BookItem::Chapter(ref mut chapter) = *item {
+            eprintln!("{}: processing chapter '{}'", NAME, chapter.name);
+
+            let md = remove_emphasis(num_removed_items, chapter)?;
+            chapter.content = md;
         }
     }
+
+    Ok(())
 }
 
-fn do_it(book: OsString) -> Result<()> {
-    let mut book = MDBook::load(book)?;
-    book.with_preprecessor(Deemphasize);
-    book.build()
-}
+fn remove_emphasis(num_removed_items: &mut usize, chapter: &mut Chapter) -> Result<String> {
+    let mut buf = String::with_capacity(chapter.content.len());
 
-fn main() {
-    if args_os().count() != 2 {
-        eprintln!("USAGE: {} <book>", args().next().expect("executable"));
-        return;
-    }
-    if let Err(e) = do_it(args_os().skip(1).next().expect("one argument")) {
-        eprintln!("{}", e);
-        process::exit(1);
-    }
-}
+    let events = Parser::new(&chapter.content).filter(|e| {
+        let should_keep = match *e {
+            Event::Start(Tag::Emphasis)
+            | Event::Start(Tag::Strong)
+            | Event::End(Tag::Emphasis)
+            | Event::End(Tag::Strong) => false,
+            _ => true,
+        };
+        if !should_keep {
+            *num_removed_items += 1;
+        }
+        should_keep
+    });
 
-impl Deemphasize {
-    fn remove_emphasis(num_removed_items: &mut i32, chapter: &mut Chapter) -> Result<String> {
-        let mut buf = String::with_capacity(chapter.content.len());
-        let events = Parser::new(&chapter.content).filter(|e| {
-            let should_keep = match *e {
-                Event::Start(Tag::Emphasis)
-                | Event::Start(Tag::Strong)
-                | Event::End(Tag::Emphasis)
-                | Event::End(Tag::Strong) => false,
-                _ => true,
-            };
-            if !should_keep {
-                *num_removed_items += 1;
-            }
-            should_keep
-        });
-        cmark(events, &mut buf, None)
-            .map(|_| buf)
-            .map_err(|err| Error::from(format!("Markdown serialization failed: {}", err)))
-    }
+    cmark(events, &mut buf, None)
+        .map(|_| buf)
+        .map_err(|err| Error::from(format!("Markdown serialization failed: {}", err)))
 }

examples/nop-preprocessor.rs

@@ -0,0 +1,108 @@
+extern crate clap;
+extern crate mdbook;
+extern crate serde_json;
+
+use clap::{App, Arg, ArgMatches, SubCommand};
+use mdbook::book::Book;
+use mdbook::errors::Error;
+use mdbook::preprocess::{CmdPreprocessor, Preprocessor, PreprocessorContext};
+use nop_lib::Nop;
+use std::io;
+use std::process;
+
+pub fn make_app() -> App<'static, 'static> {
+    App::new("nop-preprocessor")
+        .about("A mdbook preprocessor which does precisely nothing")
+        .subcommand(
+            SubCommand::with_name("supports")
+                .arg(Arg::with_name("renderer").required(true))
+                .about("Check whether a renderer is supported by this preprocessor"),
+        )
+}
+
+fn main() {
+    let matches = make_app().get_matches();
+
+    // Users will want to construct their own preprocessor here
+    let preprocessor = Nop::new();
+
+    if let Some(sub_args) = matches.subcommand_matches("supports") {
+        handle_supports(&preprocessor, sub_args);
+    } else {
+        if let Err(e) = handle_preprocessing(&preprocessor) {
+            eprintln!("{}", e);
+            process::exit(1);
+        }
+    }
+}
+
+fn handle_preprocessing(pre: &dyn Preprocessor) -> Result<(), Error> {
+    let (ctx, book) = CmdPreprocessor::parse_input(io::stdin())?;
+
+    if ctx.mdbook_version != mdbook::MDBOOK_VERSION {
+        // We should probably use the `semver` crate to check compatibility
+        // here...
+        eprintln!(
+            "Warning: The {} plugin was built against version {} of mdbook, \
+             but we're being called from version {}",
+            pre.name(),
+            mdbook::MDBOOK_VERSION,
+            ctx.mdbook_version
+        );
+    }
+
+    let processed_book = pre.run(&ctx, book)?;
+    serde_json::to_writer(io::stdout(), &processed_book)?;
+
+    Ok(())
+}
+
+fn handle_supports(pre: &dyn Preprocessor, sub_args: &ArgMatches) -> ! {
+    let renderer = sub_args.value_of("renderer").expect("Required argument");
+    let supported = pre.supports_renderer(&renderer);
+
+    // Signal whether the renderer is supported by exiting with 1 or 0.
+    if supported {
+        process::exit(0);
+    } else {
+        process::exit(1);
+    }
+}
+
+/// The actual implementation of the `Nop` preprocessor. This would usually go
+/// in your main `lib.rs` file.
+mod nop_lib {
+    use super::*;
+
+    /// A no-op preprocessor.
+    pub struct Nop;
+
+    impl Nop {
+        pub fn new() -> Nop {
+            Nop
+        }
+    }
+
+    impl Preprocessor for Nop {
+        fn name(&self) -> &str {
+            "nop-preprocessor"
+        }
+
+        fn run(&self, ctx: &PreprocessorContext, book: Book) -> Result<Book, Error> {
+            // In testing we want to tell the preprocessor to blow up by setting a
+            // particular config value
+            if let Some(nop_cfg) = ctx.config.get_preprocessor(self.name()) {
+                if nop_cfg.contains_key("blow-up") {
+                    return Err("Boom!!1!".into());
+                }
+            }
+
+            // we *are* a no-op preprocessor after all
+            Ok(book)
+        }
+
+        fn supports_renderer(&self, renderer: &str) -> bool {
+            renderer != "not-supported"
+        }
+    }
+}

src/book/book.rs

@@ -167,9 +167,9 @@ impl Chapter {
     ) -> Chapter {
         Chapter {
             name: name.to_string(),
-            content: content,
+            content,
             path: path.into(),
-            parent_names: parent_names,
+            parent_names,
             ..Default::default()
         }
     }
@@ -210,7 +210,7 @@ fn load_summary_item<P: AsRef<Path>>(
     match *item {
         SummaryItem::Separator => Ok(BookItem::Separator),
         SummaryItem::Link(ref link) => {
-            load_chapter(link, src_dir, parent_names).map(|c| BookItem::Chapter(c))
+            load_chapter(link, src_dir, parent_names).map(BookItem::Chapter)
         }
     }
 }
@@ -245,7 +245,8 @@ fn load_chapter<P: AsRef<Path>>(
     ch.number = link.number.clone();
 
     sub_item_parents.push(link.name.clone());
-    let sub_items = link.nested_items
+    let sub_items = link
+        .nested_items
         .iter()
         .map(|i| load_summary_item(i, src_dir, sub_item_parents.clone()))
         .collect::<Result<Vec<_>>>()?;
@@ -475,12 +476,12 @@ And here is some \
         assert_eq!(got.len(), 5);
 
         // checking the chapter names are in the order should be sufficient here...
-        let chapter_names: Vec<String> = got.into_iter()
+        let chapter_names: Vec<String> = got
+            .into_iter()
             .filter_map(|i| match *i {
                 BookItem::Chapter(ref ch) => Some(ch.name.clone()),
                 _ => None,
-            })
-            .collect();
+            }).collect();
         let should_be: Vec<_> = vec![
             String::from("Chapter 1"),
             String::from("Hello World"),

src/book/init.rs

@@ -110,7 +110,8 @@ impl BookBuilder {
     fn copy_across_theme(&self) -> Result<()> {
         debug!("Copying theme");
 
-        let themedir = self.config
+        let themedir = self
+            .config
             .html_config()
             .and_then(|html| html.theme)
             .unwrap_or_else(|| self.config.book.src.join("theme"));
@@ -174,7 +175,7 @@ impl BookBuilder {
         let summary = src_dir.join("SUMMARY.md");
         let mut f = File::create(&summary).chain_err(|| "Unable to create SUMMARY.md")?;
         writeln!(f, "# Summary")?;
-        writeln!(f, "")?;
+        writeln!(f)?;
         writeln!(f, "- [Chapter 1](./chapter_1.md)")?;
 
         let chapter_1 = src_dir.join("chapter_1.md");

src/book/mod.rs

@@ -20,7 +20,9 @@ use tempfile::Builder as TempFileBuilder;
 use toml::Value;
 
 use errors::*;
-use preprocess::{IndexPreprocessor, LinkPreprocessor, Preprocessor, PreprocessorContext};
+use preprocess::{
+    CmdPreprocessor, IndexPreprocessor, LinkPreprocessor, Preprocessor, PreprocessorContext,
+};
 use renderer::{CmdRenderer, HtmlHandlebars, RenderContext, Renderer};
 use utils;
 
@@ -149,23 +151,36 @@ impl MDBook {
     pub fn build(&self) -> Result<()> {
         info!("Book building has started");
 
-        let mut preprocessed_book = self.book.clone();
-        let preprocess_ctx = PreprocessorContext::new(self.root.clone(), self.config.clone());
-
-        for preprocessor in &self.preprocessors {
-            debug!("Running the {} preprocessor.", preprocessor.name());
-            preprocessor.run(&preprocess_ctx, &mut preprocessed_book)?;
-        }
-
         for renderer in &self.renderers {
-            info!("Running the {} backend", renderer.name());
-            self.run_renderer(&preprocessed_book, renderer.as_ref())?;
+            self.execute_build_process(&**renderer)?;
         }
 
         Ok(())
     }
 
-    fn run_renderer(&self, preprocessed_book: &Book, renderer: &Renderer) -> Result<()> {
+    /// Run the entire build process for a particular `Renderer`.
+    fn execute_build_process(&self, renderer: &Renderer) -> Result<()> {
+        let mut preprocessed_book = self.book.clone();
+        let preprocess_ctx = PreprocessorContext::new(
+            self.root.clone(),
+            self.config.clone(),
+            renderer.name().to_string(),
+        );
+
+        for preprocessor in &self.preprocessors {
+            if preprocessor_should_run(&**preprocessor, renderer, &self.config) {
+                debug!("Running the {} preprocessor.", preprocessor.name());
+                preprocessed_book = preprocessor.run(&preprocess_ctx, preprocessed_book)?;
+            }
+        }
+
+        info!("Running the {} backend", renderer.name());
+        self.render(&preprocessed_book, renderer)?;
+
+        Ok(())
+    }
+
+    fn render(&self, preprocessed_book: &Book, renderer: &Renderer) -> Result<()> {
         let name = renderer.name();
         let build_dir = self.build_dir_for(name);
         if build_dir.exists() {
@@ -215,13 +230,15 @@ impl MDBook {
 
         let temp_dir = TempFileBuilder::new().prefix("mdbook-").tempdir()?;
 
-        let preprocess_context = PreprocessorContext::new(self.root.clone(), self.config.clone());
+        // FIXME: Is "test" the proper renderer name to use here?
+        let preprocess_context =
+            PreprocessorContext::new(self.root.clone(), self.config.clone(), "test".to_string());
 
-        LinkPreprocessor::new().run(&preprocess_context, &mut self.book)?;
+        let book = LinkPreprocessor::new().run(&preprocess_context, self.book.clone())?;
         // Index Preprocessor is disabled so that chapter paths continue to point to the
         // actual markdown files.
 
-        for item in self.iter() {
+        for item in book.iter() {
             if let BookItem::Chapter(ref ch) = *item {
                 if !ch.path.as_os_str().is_empty() {
                     let path = self.source_dir().join(&ch.path);
@@ -330,30 +347,46 @@ fn default_preprocessors() -> Vec<Box<Preprocessor>> {
     ]
 }
 
+fn is_default_preprocessor(pre: &Preprocessor) -> bool {
+    let name = pre.name();
+    name == LinkPreprocessor::NAME || name == IndexPreprocessor::NAME
+}
+
 /// Look at the `MDBook` and try to figure out what preprocessors to run.
 fn determine_preprocessors(config: &Config) -> Result<Vec<Box<Preprocessor>>> {
-    let preprocess_list = match config.build.preprocess {
-        Some(ref p) => p,
-        // If no preprocessor field is set, default to the LinkPreprocessor and
-        // IndexPreprocessor. This allows you to disable default preprocessors
-        // by setting "preprocess" to an empty list.
-        None => return Ok(default_preprocessors()),
-    };
+    let mut preprocessors = Vec::new();
 
-    let mut preprocessors: Vec<Box<Preprocessor>> = Vec::new();
+    if config.build.use_default_preprocessors {
+        preprocessors.extend(default_preprocessors());
+    }
 
-    for key in preprocess_list {
-        match key.as_ref() {
-            "links" => preprocessors.push(Box::new(LinkPreprocessor::new())),
-            "index" => preprocessors.push(Box::new(IndexPreprocessor::new())),
-            _ => bail!("{:?} is not a recognised preprocessor", key),
+    if let Some(preprocessor_table) = config.get("preprocessor").and_then(|v| v.as_table()) {
+        for key in preprocessor_table.keys() {
+            match key.as_ref() {
+                "links" => preprocessors.push(Box::new(LinkPreprocessor::new())),
+                "index" => preprocessors.push(Box::new(IndexPreprocessor::new())),
+                name => preprocessors.push(interpret_custom_preprocessor(
+                    name,
+                    &preprocessor_table[name],
+                )),
+            }
         }
     }
 
     Ok(preprocessors)
 }
 
-fn interpret_custom_renderer(key: &str, table: &Value) -> Box<Renderer> {
+fn interpret_custom_preprocessor(key: &str, table: &Value) -> Box<CmdPreprocessor> {
+    let command = table
+        .get("command")
+        .and_then(|c| c.as_str())
+        .map(|s| s.to_string())
+        .unwrap_or_else(|| format!("mdbook-{}", key));
+
+    Box::new(CmdPreprocessor::new(key.to_string(), command.to_string()))
+}
+
+fn interpret_custom_renderer(key: &str, table: &Value) -> Box<CmdRenderer> {
     // look for the `command` field, falling back to using the key
     // prepended by "mdbook-"
     let table_dot_command = table
@@ -366,6 +399,31 @@ fn interpret_custom_renderer(key: &str, table: &Value) -> Box<Renderer> {
     Box::new(CmdRenderer::new(key.to_string(), command.to_string()))
 }
 
+/// Check whether we should run a particular `Preprocessor` in combination
+/// with the renderer, falling back to `Preprocessor::supports_renderer()`
+/// method if the user doesn't say anything.
+///
+/// The `build.use-default-preprocessors` config option can be used to ensure
+/// default preprocessors always run if they support the renderer.
+fn preprocessor_should_run(preprocessor: &Preprocessor, renderer: &Renderer, cfg: &Config) -> bool {
+    // default preprocessors should be run by default (if supported)
+    if cfg.build.use_default_preprocessors && is_default_preprocessor(preprocessor) {
+        return preprocessor.supports_renderer(renderer.name());
+    }
+
+    let key = format!("preprocessor.{}.renderers", preprocessor.name());
+    let renderer_name = renderer.name();
+
+    if let Some(Value::Array(ref explicit_renderers)) = cfg.get(&key) {
+        return explicit_renderers
+            .iter()
+            .filter_map(|val| val.as_str())
+            .any(|name| name == renderer_name);
+    }
+
+    preprocessor.supports_renderer(renderer_name)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -413,8 +471,8 @@ mod tests {
     fn config_defaults_to_link_and_index_preprocessor_if_not_set() {
         let cfg = Config::default();
 
-        // make sure we haven't got anything in the `output` table
-        assert!(cfg.build.preprocess.is_none());
+        // make sure we haven't got anything in the `preprocessor` table
+        assert!(cfg.get("preprocessor").is_none());
 
         let got = determine_preprocessors(&cfg);
 
@@ -425,47 +483,105 @@ mod tests {
     }
 
     #[test]
-    fn config_doesnt_default_if_empty() {
-        let cfg_str: &'static str = r#"
-        [book]
-        title = "Some Book"
+    fn use_default_preprocessors_works() {
+        let mut cfg = Config::default();
+        cfg.build.use_default_preprocessors = false;
 
-        [build]
-        build-dir = "outputs"
-        create-missing = false
-        preprocess = []
-        "#;
+        let got = determine_preprocessors(&cfg).unwrap();
 
-        let cfg = Config::from_str(cfg_str).unwrap();
-
-        // make sure we have something in the `output` table
-        assert!(cfg.build.preprocess.is_some());
-
-        let got = determine_preprocessors(&cfg);
-
-        assert!(got.is_ok());
-        assert!(got.unwrap().is_empty());
+        assert_eq!(got.len(), 0);
     }
 
     #[test]
-    fn config_complains_if_unimplemented_preprocessor() {
+    fn can_determine_third_party_preprocessors() {
         let cfg_str: &'static str = r#"
         [book]
         title = "Some Book"
 
+        [preprocessor.random]
+
         [build]
         build-dir = "outputs"
         create-missing = false
-        preprocess = ["random"]
         "#;
 
         let cfg = Config::from_str(cfg_str).unwrap();
 
-        // make sure we have something in the `output` table
-        assert!(cfg.build.preprocess.is_some());
+        // make sure the `preprocessor.random` table exists
+        assert!(cfg.get_preprocessor("random").is_some());
 
-        let got = determine_preprocessors(&cfg);
+        let got = determine_preprocessors(&cfg).unwrap();
 
-        assert!(got.is_err());
+        assert!(got.into_iter().any(|p| p.name() == "random"));
+    }
+
+    #[test]
+    fn preprocessors_can_provide_their_own_commands() {
+        let cfg_str = r#"
+        [preprocessor.random]
+        command = "python random.py"
+        "#;
+
+        let cfg = Config::from_str(cfg_str).unwrap();
+
+        // make sure the `preprocessor.random` table exists
+        let random = cfg.get_preprocessor("random").unwrap();
+        let random = interpret_custom_preprocessor("random", &Value::Table(random.clone()));
+
+        assert_eq!(random.cmd(), "python random.py");
+    }
+
+    #[test]
+    fn config_respects_preprocessor_selection() {
+        let cfg_str: &'static str = r#"
+        [preprocessor.links]
+        renderers = ["html"]
+        "#;
+
+        let cfg = Config::from_str(cfg_str).unwrap();
+
+        // double-check that we can access preprocessor.links.renderers[0]
+        let html = cfg
+            .get_preprocessor("links")
+            .and_then(|links| links.get("renderers"))
+            .and_then(|renderers| renderers.as_array())
+            .and_then(|renderers| renderers.get(0))
+            .and_then(|renderer| renderer.as_str())
+            .unwrap();
+        assert_eq!(html, "html");
+        let html_renderer = HtmlHandlebars::default();
+        let pre = LinkPreprocessor::new();
+
+        let should_run = preprocessor_should_run(&pre, &html_renderer, &cfg);
+        assert!(should_run);
+    }
+
+    struct BoolPreprocessor(bool);
+    impl Preprocessor for BoolPreprocessor {
+        fn name(&self) -> &str {
+            "bool-preprocessor"
+        }
+
+        fn run(&self, _ctx: &PreprocessorContext, _book: Book) -> Result<Book> {
+            unimplemented!()
+        }
+
+        fn supports_renderer(&self, _renderer: &str) -> bool {
+            self.0
+        }
+    }
+
+    #[test]
+    fn preprocessor_should_run_falls_back_to_supports_renderer_method() {
+        let cfg = Config::default();
+        let html = HtmlHandlebars::new();
+
+        let should_be = true;
+        let got = preprocessor_should_run(&BoolPreprocessor(should_be), &html, &cfg);
+        assert_eq!(got, should_be);
+
+        let should_be = false;
+        let got = preprocessor_should_run(&BoolPreprocessor(should_be), &html, &cfg);
+        assert_eq!(got, should_be);
     }
 }

src/book/summary.rs

@@ -221,11 +221,14 @@ impl<'a> SummaryParser<'a> {
     fn parse(mut self) -> Result<Summary> {
         let title = self.parse_title();
 
-        let prefix_chapters = self.parse_affix(true)
+        let prefix_chapters = self
+            .parse_affix(true)
             .chain_err(|| "There was an error parsing the prefix chapters")?;
-        let numbered_chapters = self.parse_numbered()
+        let numbered_chapters = self
+            .parse_numbered()
             .chain_err(|| "There was an error parsing the numbered chapters")?;
-        let suffix_chapters = self.parse_affix(false)
+        let suffix_chapters = self
+            .parse_affix(false)
             .chain_err(|| "There was an error parsing the suffix chapters")?;
 
         Ok(Summary {
@@ -277,7 +280,7 @@ impl<'a> SummaryParser<'a> {
             Err(self.parse_error("You can't have an empty link."))
         } else {
             Ok(Link {
-                name: name,
+                name,
                 location: PathBuf::from(href.to_string()),
                 number: None,
                 nested_items: Vec::new(),
@@ -289,6 +292,7 @@ impl<'a> SummaryParser<'a> {
     /// already been consumed by a previous parser.
     fn parse_numbered(&mut self) -> Result<Vec<SummaryItem>> {
         let mut items = Vec::new();
+        let mut root_items = 0;
         let root_number = SectionNumber::default();
 
         // we need to do this funny loop-match-if-let dance because a rule will
@@ -305,7 +309,8 @@ impl<'a> SummaryParser<'a> {
             // if we've resumed after something like a rule the root sections
             // will be numbered from 1. We need to manually go back and update
             // them
-            update_section_numbers(&mut bunch_of_items, 0, items.len() as u32);
+            update_section_numbers(&mut bunch_of_items, 0, root_items);
+            root_items += bunch_of_items.len() as u32;
             items.extend(bunch_of_items);
 
             match self.next_event() {
@@ -472,8 +477,7 @@ fn stringify_events(events: Vec<Event>) -> String {
         .filter_map(|t| match t {
             Event::Text(text) => Some(text.into_owned()),
             _ => None,
-        })
-        .collect()
+        }).collect()
 }
 
 /// A section number like "1.2.3", basically just a newtype'd `Vec<u32>` with
@@ -722,4 +726,41 @@ mod tests {
         let got = parser.parse_numbered();
         assert!(got.is_err());
     }
+
+    /// Regression test for https://github.com/rust-lang-nursery/mdBook/issues/779
+    /// Ensure section numbers are correctly incremented after a horizontal separator.
+    #[test]
+    fn keep_numbering_after_separator() {
+        let src =
+            "- [First](./first.md)\n---\n- [Second](./second.md)\n---\n- [Third](./third.md)\n";
+        let should_be = vec![
+            SummaryItem::Link(Link {
+                name: String::from("First"),
+                location: PathBuf::from("./first.md"),
+                number: Some(SectionNumber(vec![1])),
+                nested_items: Vec::new(),
+            }),
+            SummaryItem::Separator,
+            SummaryItem::Link(Link {
+                name: String::from("Second"),
+                location: PathBuf::from("./second.md"),
+                number: Some(SectionNumber(vec![2])),
+                nested_items: Vec::new(),
+            }),
+            SummaryItem::Separator,
+            SummaryItem::Link(Link {
+                name: String::from("Third"),
+                location: PathBuf::from("./third.md"),
+                number: Some(SectionNumber(vec![3])),
+                nested_items: Vec::new(),
+            }),
+        ];
+
+        let mut parser = SummaryParser::new(src);
+        let _ = parser.stream.next();
+
+        let got = parser.parse_numbered().unwrap();
+
+        assert_eq!(got, should_be);
+    }
 }

src/cmd/build.rs

@@ -9,13 +9,12 @@ pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
         .about("Builds a book from its markdown files")
         .arg_from_usage(
             "-d, --dest-dir=[dest-dir] 'Output directory for the book{n}\
-             (If omitted, uses build.build-dir from book.toml or defaults to ./book)'",
-        )
-        .arg_from_usage(
+             Relative paths are interpreted relative to the book's root directory.{n}\
+             If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.'",
+        ).arg_from_usage(
             "[dir] 'Root directory for the book{n}\
              (Defaults to the Current Directory when omitted)'",
-        )
-        .arg_from_usage("-o, --open 'Opens the compiled book in a web browser'")
+        ).arg_from_usage("-o, --open 'Opens the compiled book in a web browser'")
 }
 
 // Build command implementation

src/cmd/clean.rs

@@ -10,9 +10,10 @@ pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
         .about("Deletes a built book")
         .arg_from_usage(
             "-d, --dest-dir=[dest-dir] 'Output directory for the book{n}\
-             (If omitted, uses build.build-dir from book.toml or defaults to ./book)'",
-        )
-        .arg_from_usage(
+             Relative paths are interpreted relative to the book's root directory.{n}\
+             Running this command deletes this directory.{n}\
+             If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.'",
+        ).arg_from_usage(
             "[dir] 'Root directory for the book{n}\
              (Defaults to the Current Directory when omitted)'",
         )

src/cmd/init.rs

@@ -12,9 +12,10 @@ pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
     SubCommand::with_name("init")
         .about("Creates the boilerplate structure and files for a new book")
         // the {n} denotes a newline which will properly aligned in all help messages
-        .arg_from_usage("[dir] 'Directory to create the book in{n}\
-            (Defaults to the Current Directory when omitted)'")
-        .arg_from_usage("--theme 'Copies the default theme into your source folder'")
+        .arg_from_usage(
+            "[dir] 'Directory to create the book in{n}\
+             (Defaults to the Current Directory when omitted)'",
+        ).arg_from_usage("--theme 'Copies the default theme into your source folder'")
         .arg_from_usage("--force 'Skips confirmation prompts'")
 }
 

src/cmd/serve.rs

@@ -22,7 +22,8 @@ pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
         .about("Serves a book at http://localhost:3000, and rebuilds it on changes")
         .arg_from_usage(
             "-d, --dest-dir=[dest-dir] 'Output directory for the book{n}\
-             (If omitted, uses build.build-dir from book.toml or defaults to ./book)'",
+             Relative paths are interpreted relative to the book's root directory.{n}\
+             If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.'",
         )
         .arg_from_usage(
             "[dir] 'Root directory for the book{n}\
@@ -75,7 +76,7 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
     let port = args.value_of("port").unwrap();
     let ws_port = args.value_of("websocket-port").unwrap();
     let hostname = args.value_of("hostname").unwrap();
-    let public_address = args.value_of("websocket-address").unwrap_or(hostname);
+    let public_address = args.value_of("websocket-hostname").unwrap_or(hostname);
     let open_browser = args.is_present("open");
 
     let address = format!("{}:{}", hostname, port);
@@ -114,7 +115,7 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
     }
 
     #[cfg(feature = "watch")]
-    watch::trigger_on_change(&mut book, move |path, book_dir| {
+    watch::trigger_on_change(&book, move |path, book_dir| {
         info!("File changed: {:?}", path);
         info!("Building book...");
 
@@ -122,10 +123,10 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
 
         let result = MDBook::load(&book_dir)
             .and_then(|mut b| {
-                b.config.set("output.html.livereload-url", &livereload_url)?;
+                b.config
+                    .set("output.html.livereload-url", &livereload_url)?;
                 Ok(b)
-            })
-            .and_then(|b| b.build());
+            }).and_then(|b| b.build());
 
         if let Err(e) = result {
             error!("Unable to load the book");

src/cmd/test.rs

@@ -9,7 +9,8 @@ pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
         .about("Tests that a book's Rust code samples compile")
         .arg_from_usage(
             "-d, --dest-dir=[dest-dir] 'Output directory for the book{n}\
-             (If omitted, uses build.build-dir from book.toml or defaults to ./book)'",
+             Relative paths are interpreted relative to the book's root directory.{n}\
+             If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.'",
         )
         .arg_from_usage(
             "[dir] 'Root directory for the book{n}\
@@ -28,7 +29,8 @@ pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
 
 // test command implementation
 pub fn execute(args: &ArgMatches) -> Result<()> {
-    let library_paths: Vec<&str> = args.values_of("library-path")
+    let library_paths: Vec<&str> = args
+        .values_of("library-path")
         .map(|v| v.collect())
         .unwrap_or_default();
     let book_dir = get_book_dir(args);

src/cmd/watch.rs

@@ -16,13 +16,12 @@ pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
         .about("Watches a book's files and rebuilds it on changes")
         .arg_from_usage(
             "-d, --dest-dir=[dest-dir] 'Output directory for the book{n}\
-             (If omitted, uses build.build-dir from book.toml or defaults to ./book)'",
-        )
-        .arg_from_usage(
+             Relative paths are interpreted relative to the book's root directory.{n}\
+             If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.'",
+        ).arg_from_usage(
             "[dir] 'Root directory for the book{n}\
              (Defaults to the Current Directory when omitted)'",
-        )
-        .arg_from_usage("-o, --open 'Open the compiled book in a web browser'")
+        ).arg_from_usage("-o, --open 'Open the compiled book in a web browser'")
 }
 
 // Watch command implementation

src/config.rs

@@ -209,6 +209,18 @@ impl Config {
         Ok(())
     }
 
+    /// Get the table associated with a particular renderer.
+    pub fn get_renderer<I: AsRef<str>>(&self, index: I) -> Option<&Table> {
+        let key = format!("output.{}", index.as_ref());
+        self.get(&key).and_then(|v| v.as_table())
+    }
+
+    /// Get the table associated with a particular preprocessor.
+    pub fn get_preprocessor<I: AsRef<str>>(&self, index: I) -> Option<&Table> {
+        let key = format!("preprocessor.{}", index.as_ref());
+        self.get(&key).and_then(|v| v.as_table())
+    }
+
     fn from_legacy(mut table: Value) -> Config {
         let mut cfg = Config::default();
 
@@ -289,8 +301,8 @@ impl<'de> Deserialize<'de> for Config {
             .unwrap_or_default();
 
         Ok(Config {
-            book: book,
-            build: build,
+            book,
+            build,
             rest: Value::Table(table),
         })
     }
@@ -382,8 +394,9 @@ pub struct BuildConfig {
     /// Should non-existent markdown files specified in `SETTINGS.md` be created
     /// if they don't exist?
     pub create_missing: bool,
-    /// Which preprocessors should be applied
-    pub preprocess: Option<Vec<String>>,
+    /// Should the default preprocessors always be used when they are
+    /// compatible with the renderer?
+    pub use_default_preprocessors: bool,
 }
 
 impl Default for BuildConfig {
@@ -391,7 +404,7 @@ impl Default for BuildConfig {
         BuildConfig {
             build_dir: PathBuf::from("book"),
             create_missing: true,
-            preprocess: None,
+            use_default_preprocessors: true,
         }
     }
 }
@@ -402,6 +415,8 @@ impl Default for BuildConfig {
 pub struct HtmlConfig {
     /// The theme directory, if specified.
     pub theme: Option<PathBuf>,
+    /// The default theme to use, defaults to 'light'
+    pub default_theme: Option<String>,
     /// Use "smart quotes" instead of the usual `"` character.
     pub curly_quotes: bool,
     /// Should mathjax be enabled?
@@ -423,10 +438,15 @@ pub struct HtmlConfig {
     /// This config item *should not be edited* by the end user.
     #[doc(hidden)]
     pub livereload_url: Option<String>,
-    /// Should section labels be rendered?
+    /// Don't render section labels.
     pub no_section_label: bool,
     /// Search settings. If `None`, the default will be used.
     pub search: Option<Search>,
+    /// Git repository url. If `None`, the git button will not be shown.
+    pub git_repository_url: Option<String>,
+    /// FontAwesome icon class to use for the Git repository link.
+    /// Defaults to `fa-github` if `None`.
+    pub git_repository_icon: Option<String>,
 }
 
 impl HtmlConfig {
@@ -534,11 +554,7 @@ trait Updateable<'de>: Serialize + Deserialize<'de> {
     }
 }
 
-impl<'de, T> Updateable<'de> for T
-where
-    T: Serialize + Deserialize<'de>,
-{
-}
+impl<'de, T> Updateable<'de> for T where T: Serialize + Deserialize<'de> {}
 
 #[cfg(test)]
 mod tests {
@@ -555,17 +571,24 @@ mod tests {
         [build]
         build-dir = "outputs"
         create-missing = false
-        preprocess = ["first_preprocessor", "second_preprocessor"]
+        use-default-preprocessors = true
 
         [output.html]
         theme = "./themedir"
+        default-theme = "rust"
         curly-quotes = true
         google-analytics = "123456"
         additional-css = ["./foo/bar/baz.css"]
+        git-repository-url = "https://foo.com/"
+        git-repository-icon = "fa-code-fork"
 
         [output.html.playpen]
         editable = true
         editor = "ace"
+
+        [preprocess.first]
+
+        [preprocess.second]
         "#;
 
     #[test]
@@ -583,10 +606,7 @@ mod tests {
         let build_should_be = BuildConfig {
             build_dir: PathBuf::from("outputs"),
             create_missing: false,
-            preprocess: Some(vec![
-                "first_preprocessor".to_string(),
-                "second_preprocessor".to_string(),
-            ]),
+            use_default_preprocessors: true,
         };
         let playpen_should_be = Playpen {
             editable: true,
@@ -597,7 +617,10 @@ mod tests {
             google_analytics: Some(String::from("123456")),
             additional_css: vec![PathBuf::from("./foo/bar/baz.css")],
             theme: Some(PathBuf::from("./themedir")),
+            default_theme: Some(String::from("rust")),
             playpen: playpen_should_be,
+            git_repository_url: Some(String::from("https://foo.com/")),
+            git_repository_icon: Some(String::from("fa-code-fork")),
             ..Default::default()
         };
 
@@ -688,7 +711,7 @@ mod tests {
         let build_should_be = BuildConfig {
             build_dir: PathBuf::from("my-book"),
             create_missing: true,
-            preprocess: None,
+            use_default_preprocessors: true,
         };
 
         let html_should_be = HtmlConfig {

src/lib.rs

@@ -114,6 +114,12 @@ pub mod renderer;
 pub mod theme;
 pub mod utils;
 
+/// The current version of `mdbook`.
+///
+/// This is provided as a way for custom preprocessors and renderers to do
+/// compatibility checks.
+pub const MDBOOK_VERSION: &str = env!("CARGO_PKG_VERSION");
+
 pub use book::BookItem;
 pub use book::MDBook;
 pub use config::Config;

src/main.rs

@@ -20,8 +20,8 @@ use std::path::{Path, PathBuf};
 
 mod cmd;
 
-const NAME: &'static str = "mdBook";
-const VERSION: &'static str = concat!("v", crate_version!());
+const NAME: &str = "mdBook";
+const VERSION: &str = concat!("v", crate_version!());
 
 fn main() {
     init_logger();

src/preprocess/cmd.rs

@@ -0,0 +1,197 @@
+use super::{Preprocessor, PreprocessorContext};
+use book::Book;
+use errors::*;
+use serde_json;
+use shlex::Shlex;
+use std::io::{self, Read, Write};
+use std::process::{Child, Command, Stdio};
+
+/// A custom preprocessor which will shell out to a 3rd-party program.
+///
+/// # Preprocessing Protocol
+///
+/// When the `supports_renderer()` method is executed, `CmdPreprocessor` will
+/// execute the shell command `$cmd supports $renderer`. If the renderer is
+/// supported, custom preprocessors should exit with a exit code of `0`,
+/// any other exit code be considered as unsupported.
+///
+/// The `run()` method is implemented by passing a `(PreprocessorContext, Book)`
+/// tuple to the spawned command (`$cmd`) as JSON via `stdin`. Preprocessors
+/// should then "return" a processed book by printing it to `stdout` as JSON.
+/// For convenience, the `CmdPreprocessor::parse_input()` function can be used
+/// to parse the input provided by `mdbook`.
+///
+/// Exiting with a non-zero exit code while preprocessing is considered an
+/// error. `stderr` is passed directly through to the user, so it can be used
+/// for logging or emitting warnings if desired.
+///
+/// # Examples
+///
+/// An example preprocessor is available in this project's `examples/`
+/// directory.
+#[derive(Debug, Clone, PartialEq)]
+pub struct CmdPreprocessor {
+    name: String,
+    cmd: String,
+}
+
+impl CmdPreprocessor {
+    /// Create a new `CmdPreprocessor`.
+    pub fn new(name: String, cmd: String) -> CmdPreprocessor {
+        CmdPreprocessor { name, cmd }
+    }
+
+    /// A convenience function custom preprocessors can use to parse the input
+    /// written to `stdin` by a `CmdRenderer`.
+    pub fn parse_input<R: Read>(reader: R) -> Result<(PreprocessorContext, Book)> {
+        serde_json::from_reader(reader).chain_err(|| "Unable to parse the input")
+    }
+
+    fn write_input_to_child(&self, child: &mut Child, book: &Book, ctx: &PreprocessorContext) {
+        let stdin = child.stdin.take().expect("Child has stdin");
+
+        if let Err(e) = self.write_input(stdin, &book, &ctx) {
+            // Looks like the backend hung up before we could finish
+            // sending it the render context. Log the error and keep going
+            warn!("Error writing the RenderContext to the backend, {}", e);
+        }
+    }
+
+    fn write_input<W: Write>(
+        &self,
+        writer: W,
+        book: &Book,
+        ctx: &PreprocessorContext,
+    ) -> Result<()> {
+        serde_json::to_writer(writer, &(ctx, book)).map_err(Into::into)
+    }
+
+    /// The command this `Preprocessor` will invoke.
+    pub fn cmd(&self) -> &str {
+        &self.cmd
+    }
+
+    fn command(&self) -> Result<Command> {
+        let mut words = Shlex::new(&self.cmd);
+        let executable = match words.next() {
+            Some(e) => e,
+            None => bail!("Command string was empty"),
+        };
+
+        let mut cmd = Command::new(executable);
+
+        for arg in words {
+            cmd.arg(arg);
+        }
+
+        Ok(cmd)
+    }
+}
+
+impl Preprocessor for CmdPreprocessor {
+    fn name(&self) -> &str {
+        &self.name
+    }
+
+    fn run(&self, ctx: &PreprocessorContext, book: Book) -> Result<Book> {
+        let mut cmd = self.command()?;
+
+        let mut child = cmd
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::inherit())
+            .spawn()
+            .chain_err(|| {
+                format!(
+                    "Unable to start the \"{}\" preprocessor. Is it installed?",
+                    self.name()
+                )
+            })?;
+
+        self.write_input_to_child(&mut child, &book, ctx);
+
+        let output = child
+            .wait_with_output()
+            .chain_err(|| "Error waiting for the preprocessor to complete")?;
+
+        trace!("{} exited with output: {:?}", self.cmd, output);
+        ensure!(
+            output.status.success(),
+            "The preprocessor exited unsuccessfully"
+        );
+
+        serde_json::from_slice(&output.stdout).chain_err(|| "Unable to parse the preprocessed book")
+    }
+
+    fn supports_renderer(&self, renderer: &str) -> bool {
+        debug!(
+            "Checking if the \"{}\" preprocessor supports \"{}\"",
+            self.name(),
+            renderer
+        );
+
+        let mut cmd = match self.command() {
+            Ok(c) => c,
+            Err(e) => {
+                warn!(
+                    "Unable to create the command for the \"{}\" preprocessor, {}",
+                    self.name(),
+                    e
+                );
+                return false;
+            }
+        };
+
+        let outcome = cmd
+            .arg("supports")
+            .arg(renderer)
+            .stdin(Stdio::null())
+            .stdout(Stdio::inherit())
+            .stderr(Stdio::inherit())
+            .status()
+            .map(|status| status.code() == Some(0));
+
+        if let Err(ref e) = outcome {
+            if e.kind() == io::ErrorKind::NotFound {
+                warn!(
+                    "The command wasn't found, is the \"{}\" preprocessor installed?",
+                    self.name
+                );
+                warn!("\tCommand: {}", self.cmd);
+            }
+        }
+
+        outcome.unwrap_or(false)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::path::Path;
+    use MDBook;
+
+    fn book_example() -> MDBook {
+        let example = Path::new(env!("CARGO_MANIFEST_DIR")).join("book-example");
+        MDBook::load(example).unwrap()
+    }
+
+    #[test]
+    fn round_trip_write_and_parse_input() {
+        let cmd = CmdPreprocessor::new("test".to_string(), "test".to_string());
+        let md = book_example();
+        let ctx = PreprocessorContext::new(
+            md.root.clone(),
+            md.config.clone(),
+            "some-renderer".to_string(),
+        );
+
+        let mut buffer = Vec::new();
+        cmd.write_input(&mut buffer, &md.book, &ctx).unwrap();
+
+        let (got_ctx, got_book) = CmdPreprocessor::parse_input(buffer.as_slice()).unwrap();
+
+        assert_eq!(got_book, md.book);
+        assert_eq!(got_ctx, ctx);
+    }
+}

src/preprocess/index.rs

@@ -7,10 +7,12 @@ use super::{Preprocessor, PreprocessorContext};
 use book::{Book, BookItem};
 
 /// A preprocessor for converting file name `README.md` to `index.md` since
-/// `README.md` is the de facto index file in a markdown-based documentation.
+/// `README.md` is the de facto index file in markdown-based documentation.
 pub struct IndexPreprocessor;
 
 impl IndexPreprocessor {
+    pub(crate) const NAME: &'static str = "index";
+
     /// Create a new `IndexPreprocessor`.
     pub fn new() -> Self {
         IndexPreprocessor
@@ -19,10 +21,10 @@ impl IndexPreprocessor {
 
 impl Preprocessor for IndexPreprocessor {
     fn name(&self) -> &str {
-        "index"
+        Self::NAME
     }
 
-    fn run(&self, ctx: &PreprocessorContext, book: &mut Book) -> Result<()> {
+    fn run(&self, ctx: &PreprocessorContext, mut book: Book) -> Result<Book> {
         let source_dir = ctx.root.join(&ctx.config.book.src);
         book.for_each_mut(|section: &mut BookItem| {
             if let BookItem::Chapter(ref mut ch) = *section {
@@ -37,7 +39,7 @@ impl Preprocessor for IndexPreprocessor {
             }
         });
 
-        Ok(())
+        Ok(book)
     }
 }
 

src/preprocess/links.rs

@@ -16,6 +16,8 @@ const MAX_LINK_NESTED_DEPTH: usize = 10;
 pub struct LinkPreprocessor;
 
 impl LinkPreprocessor {
+    pub(crate) const NAME: &'static str = "links";
+
     /// Create a new `LinkPreprocessor`.
     pub fn new() -> Self {
         LinkPreprocessor
@@ -24,10 +26,10 @@ impl LinkPreprocessor {
 
 impl Preprocessor for LinkPreprocessor {
     fn name(&self) -> &str {
-        "links"
+        Self::NAME
     }
 
-    fn run(&self, ctx: &PreprocessorContext, book: &mut Book) -> Result<()> {
+    fn run(&self, ctx: &PreprocessorContext, mut book: Book) -> Result<Book> {
         let src_dir = ctx.root.join(&ctx.config.book.src);
 
         book.for_each_mut(|section: &mut BookItem| {
@@ -43,7 +45,7 @@ impl Preprocessor for LinkPreprocessor {
             }
         });
 
-        Ok(())
+        Ok(book)
     }
 }
 
@@ -81,6 +83,10 @@ where
             }
             Err(e) => {
                 error!("Error updating \"{}\", {}", playpen.link_text, e);
+                for cause in e.iter().skip(1) {
+                    warn!("Caused By: {}", cause);
+                }
+
                 // This should make sure we include the raw `{{# ... }}` snippet
                 // in the page content if there are any errors.
                 previous_end_index = playpen.start_index;
@@ -136,27 +142,21 @@ fn parse_include_path(path: &str) -> LinkType<'static> {
     let end = end.and_then(|s| s.parse::<usize>().ok());
     match start {
         Some(start) => match end {
-            Some(end) => LinkType::IncludeRange(
-                path,
-                Range {
-                    start: start,
-                    end: end,
-                },
-            ),
+            Some(end) => LinkType::IncludeRange(path, Range { start, end }),
             None => if has_end {
-                LinkType::IncludeRangeFrom(path, RangeFrom { start: start })
+                LinkType::IncludeRangeFrom(path, RangeFrom { start })
             } else {
                 LinkType::IncludeRange(
                     path,
                     Range {
-                        start: start,
+                        start,
                         end: start + 1,
                     },
                 )
             },
         },
         None => match end {
-            Some(end) => LinkType::IncludeRangeTo(path, RangeTo { end: end }),
+            Some(end) => LinkType::IncludeRangeTo(path, RangeTo { end }),
             None => LinkType::IncludeRangeFull(path, RangeFull),
         },
     }
@@ -205,20 +205,66 @@ impl<'a> Link<'a> {
         match self.link {
             // omit the escape char
             LinkType::Escaped => Ok((&self.link_text[1..]).to_owned()),
-            LinkType::IncludeRange(ref pat, ref range) => file_to_string(base.join(pat))
-                .map(|s| take_lines(&s, range.clone()))
-                .chain_err(|| format!("Could not read file for link {}", self.link_text)),
-            LinkType::IncludeRangeFrom(ref pat, ref range) => file_to_string(base.join(pat))
-                .map(|s| take_lines(&s, range.clone()))
-                .chain_err(|| format!("Could not read file for link {}", self.link_text)),
-            LinkType::IncludeRangeTo(ref pat, ref range) => file_to_string(base.join(pat))
-                .map(|s| take_lines(&s, range.clone()))
-                .chain_err(|| format!("Could not read file for link {}", self.link_text)),
-            LinkType::IncludeRangeFull(ref pat, _) => file_to_string(base.join(pat))
-                .chain_err(|| format!("Could not read file for link {}", self.link_text)),
+            LinkType::IncludeRange(ref pat, ref range) => {
+                let target = base.join(pat);
+
+                file_to_string(&target)
+                    .map(|s| take_lines(&s, range.clone()))
+                    .chain_err(|| {
+                        format!(
+                            "Could not read file for link {} ({})",
+                            self.link_text,
+                            target.display(),
+                        )
+                    })
+            }
+            LinkType::IncludeRangeFrom(ref pat, ref range) => {
+                let target = base.join(pat);
+
+                file_to_string(&target)
+                    .map(|s| take_lines(&s, range.clone()))
+                    .chain_err(|| {
+                        format!(
+                            "Could not read file for link {} ({})",
+                            self.link_text,
+                            target.display(),
+                        )
+                    })
+            }
+            LinkType::IncludeRangeTo(ref pat, ref range) => {
+                let target = base.join(pat);
+
+                file_to_string(&target)
+                    .map(|s| take_lines(&s, *range))
+                    .chain_err(|| {
+                        format!(
+                            "Could not read file for link {} ({})",
+                            self.link_text,
+                            target.display(),
+                        )
+                    })
+            }
+            LinkType::IncludeRangeFull(ref pat, _) => {
+                let target = base.join(pat);
+
+                file_to_string(&target).chain_err(|| {
+                    format!(
+                        "Could not read file for link {} ({})",
+                        self.link_text,
+                        target.display()
+                    )
+                })
+            }
             LinkType::Playpen(ref pat, ref attrs) => {
-                let contents = file_to_string(base.join(pat))
-                    .chain_err(|| format!("Could not read file for link {}", self.link_text))?;
+                let target = base.join(pat);
+
+                let contents = file_to_string(&target).chain_err(|| {
+                    format!(
+                        "Could not read file for link {} ({})",
+                        self.link_text,
+                        target.display()
+                    )
+                })?;
                 let ftype = if !attrs.is_empty() { "rust," } else { "rust" };
                 Ok(format!(
                     "```{}{}\n{}\n```\n",

src/preprocess/mod.rs

@@ -1,8 +1,10 @@
 //! Book preprocessing.
 
+pub use self::cmd::CmdPreprocessor;
 pub use self::index::IndexPreprocessor;
 pub use self::links::LinkPreprocessor;
 
+mod cmd;
 mod index;
 mod links;
 
@@ -14,17 +16,30 @@ use std::path::PathBuf;
 
 /// Extra information for a `Preprocessor` to give them more context when
 /// processing a book.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct PreprocessorContext {
     /// The location of the book directory on disk.
     pub root: PathBuf,
     /// The book configuration (`book.toml`).
     pub config: Config,
+    /// The `Renderer` this preprocessor is being used with.
+    pub renderer: String,
+    /// The calling `mdbook` version.
+    pub mdbook_version: String,
+    #[serde(skip)]
+    __non_exhaustive: (),
 }
 
 impl PreprocessorContext {
     /// Create a new `PreprocessorContext`.
-    pub(crate) fn new(root: PathBuf, config: Config) -> Self {
-        PreprocessorContext { root, config }
+    pub(crate) fn new(root: PathBuf, config: Config, renderer: String) -> Self {
+        PreprocessorContext {
+            root,
+            config,
+            renderer,
+            mdbook_version: ::MDBOOK_VERSION.to_string(),
+            __non_exhaustive: (),
+        }
     }
 }
 
@@ -36,5 +51,13 @@ pub trait Preprocessor {
 
     /// Run this `Preprocessor`, allowing it to update the book before it is
     /// given to a renderer.
-    fn run(&self, ctx: &PreprocessorContext, book: &mut Book) -> Result<()>;
+    fn run(&self, ctx: &PreprocessorContext, book: Book) -> Result<Book>;
+
+    /// A hint to `MDBook` whether this preprocessor is compatible with a
+    /// particular renderer.
+    ///
+    /// By default, always returns `true`.
+    fn supports_renderer(&self, _renderer: &str) -> bool {
+        true
+    }
 }

src/renderer/html_handlebars/hbs_renderer.rs

@@ -30,73 +30,71 @@ impl HtmlHandlebars {
         print_content: &mut String,
     ) -> Result<()> {
         // FIXME: This should be made DRY-er and rely less on mutable state
-        match *item {
-            BookItem::Chapter(ref ch) => {
-                let content = ch.content.clone();
-                let content = utils::render_markdown(&content, ctx.html_config.curly_quotes);
-                print_content.push_str(&content);
+        if let BookItem::Chapter(ref ch) = *item {
+            let content = ch.content.clone();
+            let content = utils::render_markdown(&content, ctx.html_config.curly_quotes);
 
-                // Update the context with data for this file
-                let path = ch.path
-                    .to_str()
-                    .chain_err(|| "Could not convert path to str")?;
-                let filepath = Path::new(&ch.path).with_extension("html");
+            let string_path = ch.path.parent().unwrap().display().to_string();
 
-                // "print.html" is used for the print page.
-                if ch.path == Path::new("print.md") {
-                    bail!(ErrorKind::ReservedFilenameError(ch.path.clone()));
-                };
+            let fixed_content = utils::render_markdown_with_base(&ch.content, ctx.html_config.curly_quotes, &string_path);
+            print_content.push_str(&fixed_content);
 
-                // Non-lexical lifetimes needed :'(
-                let title: String;
-                {
-                    let book_title = ctx.data
-                        .get("book_title")
-                        .and_then(serde_json::Value::as_str)
-                        .unwrap_or("");
-                    title = ch.name.clone() + " - " + book_title;
-                }
+            // Update the context with data for this file
+            let path = ch
+                .path
+                .to_str()
+                .chain_err(|| "Could not convert path to str")?;
+            let filepath = Path::new(&ch.path).with_extension("html");
 
-                ctx.data.insert("path".to_owned(), json!(path));
-                ctx.data.insert("content".to_owned(), json!(content));
-                ctx.data.insert("chapter_title".to_owned(), json!(ch.name));
-                ctx.data.insert("title".to_owned(), json!(title));
-                ctx.data.insert(
-                    "path_to_root".to_owned(),
-                    json!(utils::fs::path_to_root(&ch.path)),
-                );
+            // "print.html" is used for the print page.
+            if ch.path == Path::new("print.md") {
+                bail!(ErrorKind::ReservedFilenameError(ch.path.clone()));
+            };
 
-                // Render the handlebars template with the data
-                debug!("Render template");
-                let rendered = ctx.handlebars.render("index", &ctx.data)?;
-
-                let rendered = self.post_process(rendered, &ctx.html_config.playpen);
-
-                // Write to file
-                debug!("Creating {}", filepath.display());
-                utils::fs::write_file(&ctx.destination, &filepath, rendered.as_bytes())?;
-
-                if ctx.is_index {
-                    ctx.data.insert("path".to_owned(), json!("index.html"));
-                    ctx.data.insert("path_to_root".to_owned(), json!(""));
-                    let rendered_index = ctx.handlebars.render("index", &ctx.data)?;
-                    let rendered_index =
-                        self.post_process(rendered_index, &ctx.html_config.playpen);
-                    debug!("Creating index.html from {}", path);
-                    utils::fs::write_file(
-                        &ctx.destination,
-                        "index.html",
-                        rendered_index.as_bytes(),
-                    )?;
-                }
+            // Non-lexical lifetimes needed :'(
+            let title: String;
+            {
+                let book_title = ctx
+                    .data
+                    .get("book_title")
+                    .and_then(serde_json::Value::as_str)
+                    .unwrap_or("");
+                title = ch.name.clone() + " - " + book_title;
+            }
+
+            ctx.data.insert("path".to_owned(), json!(path));
+            ctx.data.insert("content".to_owned(), json!(content));
+            ctx.data.insert("chapter_title".to_owned(), json!(ch.name));
+            ctx.data.insert("title".to_owned(), json!(title));
+            ctx.data.insert(
+                "path_to_root".to_owned(),
+                json!(utils::fs::path_to_root(&ch.path)),
+            );
+
+            // Render the handlebars template with the data
+            debug!("Render template");
+            let rendered = ctx.handlebars.render("index", &ctx.data)?;
+
+            let rendered = self.post_process(rendered, &ctx.html_config.playpen);
+
+            // Write to file
+            debug!("Creating {}", filepath.display());
+            utils::fs::write_file(&ctx.destination, &filepath, rendered.as_bytes())?;
+
+            if ctx.is_index {
+                ctx.data.insert("path".to_owned(), json!("index.html"));
+                ctx.data.insert("path_to_root".to_owned(), json!(""));
+                let rendered_index = ctx.handlebars.render("index", &ctx.data)?;
+                let rendered_index = self.post_process(rendered_index, &ctx.html_config.playpen);
+                debug!("Creating index.html from {}", path);
+                utils::fs::write_file(&ctx.destination, "index.html", rendered_index.as_bytes())?;
             }
-            _ => {}
         }
 
         Ok(())
     }
 
-    #[cfg_attr(feature = "cargo-clippy", allow(let_and_return))]
+    #[cfg_attr(feature = "cargo-clippy", allow(clippy::let_and_return))]
     fn post_process(&self, rendered: String, playpen_config: &Playpen) -> String {
         let rendered = build_header_links(&rendered);
         let rendered = fix_code_blocks(&rendered);
@@ -212,6 +210,7 @@ impl HtmlHandlebars {
         );
         handlebars.register_helper("previous", Box::new(helpers::navigation::previous));
         handlebars.register_helper("next", Box::new(helpers::navigation::next));
+        handlebars.register_helper("theme_option", Box::new(helpers::theme::theme_option));
     }
 
     /// Copy across any additional CSS and JavaScript files which the book
@@ -325,7 +324,7 @@ impl Renderer for HtmlHandlebars {
                 handlebars: &handlebars,
                 destination: destination.to_path_buf(),
                 data: data.clone(),
-                is_index: is_index,
+                is_index,
                 html_config: html_config.clone(),
             };
             self.render_item(item, ctx, &mut print_content)?;
@@ -393,6 +392,12 @@ fn make_data(
         data.insert("livereload".to_owned(), json!(livereload));
     }
 
+    let default_theme = match html_config.default_theme {
+        Some(ref theme) => theme,
+        None => "light",
+    };
+    data.insert("default_theme".to_owned(), json!(default_theme));
+
     // Add google analytics tag
     if let Some(ref ga) = config.html_config().and_then(|html| html.google_analytics) {
         data.insert("google_analytics".to_owned(), json!(ga));
@@ -452,6 +457,15 @@ fn make_data(
         )
     }
 
+    if let Some(ref git_repository_url) = html_config.git_repository_url {
+        data.insert("git_repository_url".to_owned(), json!(git_repository_url));
+    }
+    let git_repository_icon = match html_config.git_repository_icon {
+        Some(ref git_repository_icon) => git_repository_icon,
+        None => "fa-github",
+    };
+    data.insert("git_repository_icon".to_owned(), json!(git_repository_icon));
+
     let mut chapters = vec![];
 
     for item in book.iter() {
@@ -465,7 +479,8 @@ fn make_data(
                 }
 
                 chapter.insert("name".to_owned(), json!(ch.name));
-                let path = ch.path
+                let path = ch
+                    .path
                     .to_str()
                     .chain_err(|| "Could not convert path to str")?;
                 chapter.insert("path".to_owned(), json!(path));
@@ -497,8 +512,7 @@ fn build_header_links(html: &str) -> String {
                 .expect("Regex should ensure we only ever get numbers here");
 
             wrap_header_with_link(level, &caps[2], &mut id_counter)
-        })
-        .into_owned()
+        }).into_owned()
 }
 
 /// Wraps a single header tag with a link, making sure each tag gets its own
@@ -549,8 +563,7 @@ fn fix_code_blocks(html: &str) -> String {
                 classes = classes,
                 after = after
             )
-        })
-        .into_owned()
+        }).into_owned()
 }
 
 fn add_playpen_pre(html: &str, playpen_config: &Playpen) -> String {
@@ -586,8 +599,7 @@ fn add_playpen_pre(html: &str, playpen_config: &Playpen) -> String {
                 // not language-rust, so no-op
                 text.to_owned()
             }
-        })
-        .into_owned()
+        }).into_owned()
 }
 
 fn partition_source(s: &str) -> (String, String) {

src/renderer/html_handlebars/helpers/mod.rs

@@ -1,2 +1,3 @@
 pub mod navigation;
+pub mod theme;
 pub mod toc;

src/renderer/html_handlebars/helpers/navigation.rs

@@ -1,7 +1,7 @@
 use std::collections::BTreeMap;
 use std::path::Path;
 
-use handlebars::{Context, Handlebars, Helper, RenderContext, RenderError, Renderable};
+use handlebars::{Context, Handlebars, Helper, Output, RenderContext, RenderError, Renderable};
 use serde_json;
 
 use utils;
@@ -18,13 +18,13 @@ impl Target {
     /// Returns target if found.
     fn find(
         &self,
-        base_path: &String,
-        current_path: &String,
+        base_path: &str,
+        current_path: &str,
         current_item: &StringMap,
         previous_item: &StringMap,
     ) -> Result<Option<StringMap>, RenderError> {
-        match self {
-            &Target::Next => {
+        match *self {
+            Target::Next => {
                 let previous_path = previous_item
                     .get("path")
                     .ok_or_else(|| RenderError::new("No path found for chapter in JSON data"))?;
@@ -34,7 +34,7 @@ impl Target {
                 }
             }
 
-            &Target::Previous => {
+            Target::Previous => {
                 if current_path == base_path {
                     return Ok(Some(previous_item.clone()));
                 }
@@ -45,15 +45,20 @@ impl Target {
     }
 }
 
-fn find_chapter(rc: &mut RenderContext, target: Target) -> Result<Option<StringMap>, RenderError> {
+fn find_chapter(
+    ctx: &Context,
+    rc: &mut RenderContext,
+    target: Target,
+) -> Result<Option<StringMap>, RenderError> {
     debug!("Get data from context");
 
-    let chapters = rc.evaluate_absolute("chapters", true).and_then(|c| {
+    let chapters = rc.evaluate_absolute(ctx, "chapters", true).and_then(|c| {
         serde_json::value::from_value::<Vec<StringMap>>(c.clone())
             .map_err(|_| RenderError::new("Could not decode the JSON data"))
     })?;
 
-    let base_path = rc.evaluate_absolute("path", true)?
+    let base_path = rc
+        .evaluate_absolute(ctx, "path", true)?
         .as_str()
         .ok_or_else(|| RenderError::new("Type error for `path`, string expected"))?
         .replace("\"", "");
@@ -83,13 +88,16 @@ fn find_chapter(rc: &mut RenderContext, target: Target) -> Result<Option<StringM
 fn render(
     _h: &Helper,
     r: &Handlebars,
+    ctx: &Context,
     rc: &mut RenderContext,
+    out: &mut Output,
     chapter: &StringMap,
 ) -> Result<(), RenderError> {
     trace!("Creating BTreeMap to inject in context");
 
     let mut context = BTreeMap::new();
-    let base_path = rc.evaluate_absolute("path", false)?
+    let base_path = rc
+        .evaluate_absolute(ctx, "path", false)?
         .as_str()
         .ok_or_else(|| RenderError::new("Type error for `path`, string expected"))?
         .replace("\"", "");
@@ -120,28 +128,41 @@ fn render(
     _h.template()
         .ok_or_else(|| RenderError::new("Error with the handlebars template"))
         .and_then(|t| {
-            let mut local_rc = rc.with_context(Context::wraps(&context)?);
-            t.render(r, &mut local_rc)
+            let mut local_rc = rc.new_for_block();
+            let local_ctx = Context::wraps(&context)?;
+            t.render(r, &local_ctx, &mut local_rc, out)
         })?;
 
     Ok(())
 }
 
-pub fn previous(_h: &Helper, r: &Handlebars, rc: &mut RenderContext) -> Result<(), RenderError> {
+pub fn previous(
+    _h: &Helper,
+    r: &Handlebars,
+    ctx: &Context,
+    rc: &mut RenderContext,
+    out: &mut Output,
+) -> Result<(), RenderError> {
     trace!("previous (handlebars helper)");
 
-    if let Some(previous) = find_chapter(rc, Target::Previous)? {
-        render(_h, r, rc, &previous)?;
+    if let Some(previous) = find_chapter(ctx, rc, Target::Previous)? {
+        render(_h, r, ctx, rc, out, &previous)?;
     }
 
     Ok(())
 }
 
-pub fn next(_h: &Helper, r: &Handlebars, rc: &mut RenderContext) -> Result<(), RenderError> {
+pub fn next(
+    _h: &Helper,
+    r: &Handlebars,
+    ctx: &Context,
+    rc: &mut RenderContext,
+    out: &mut Output,
+) -> Result<(), RenderError> {
     trace!("next (handlebars helper)");
 
-    if let Some(next) = find_chapter(rc, Target::Next)? {
-        render(_h, r, rc, &next)?;
+    if let Some(next) = find_chapter(ctx, rc, Target::Next)? {
+        render(_h, r, ctx, rc, out, &next)?;
     }
 
     Ok(())

src/renderer/html_handlebars/helpers/theme.rs

@@ -0,0 +1,30 @@
+use handlebars::{Context, Handlebars, Helper, Output, RenderContext, RenderError};
+
+pub fn theme_option(
+    h: &Helper,
+    _r: &Handlebars,
+    ctx: &Context,
+    rc: &mut RenderContext,
+    out: &mut Output,
+) -> Result<(), RenderError> {
+    trace!("theme_option (handlebars helper)");
+
+    let param = h
+        .param(0)
+        .and_then(|v| v.value().as_str())
+        .ok_or(RenderError::new(
+            "Param 0 with String type is required for theme_option helper.",
+        ))?;
+
+    let theme_name = rc
+        .evaluate_absolute(ctx, "default_theme", true)?
+        .as_str()
+        .ok_or_else(|| RenderError::new("Type error for `default_theme`, string expected"))?;
+
+    out.write(param)?;
+    if param.to_lowercase() == theme_name.to_lowercase() {
+        out.write(" (default)")?;
+    }
+
+    Ok(())
+}

src/renderer/html_handlebars/helpers/toc.rs

@@ -3,7 +3,7 @@ use std::path::Path;
 
 use utils;
 
-use handlebars::{Handlebars, Helper, HelperDef, RenderContext, RenderError};
+use handlebars::{Context, Handlebars, Helper, HelperDef, Output, RenderContext, RenderError};
 use pulldown_cmark::{html, Event, Parser, Tag};
 use serde_json;
 
@@ -14,27 +14,35 @@ pub struct RenderToc {
 }
 
 impl HelperDef for RenderToc {
-    fn call(&self, _h: &Helper, _: &Handlebars, rc: &mut RenderContext) -> Result<(), RenderError> {
+    fn call<'reg: 'rc, 'rc>(
+        &self,
+        _h: &Helper,
+        _: &Handlebars,
+        ctx: &Context,
+        rc: &mut RenderContext,
+        out: &mut Output,
+    ) -> Result<(), RenderError> {
         // get value from context data
         // rc.get_path() is current json parent path, you should always use it like this
         // param is the key of value you want to display
-        let chapters = rc.evaluate_absolute("chapters", true).and_then(|c| {
+        let chapters = rc.evaluate_absolute(ctx, "chapters", true).and_then(|c| {
             serde_json::value::from_value::<Vec<BTreeMap<String, String>>>(c.clone())
                 .map_err(|_| RenderError::new("Could not decode the JSON data"))
         })?;
-        let current = rc.evaluate_absolute("path", true)?
+        let current = rc
+            .evaluate_absolute(ctx, "path", true)?
             .as_str()
             .ok_or_else(|| RenderError::new("Type error for `path`, string expected"))?
             .replace("\"", "");
 
-        rc.writer.write_all(b"<ol class=\"chapter\">")?;
+        out.write("<ol class=\"chapter\">")?;
 
         let mut current_level = 1;
 
         for item in chapters {
             // Spacer
             if item.get("spacer").is_some() {
-                rc.writer.write_all(b"<li class=\"spacer\"></li>")?;
+                out.write("<li class=\"spacer\"></li>")?;
                 continue;
             }
 
@@ -46,30 +54,30 @@ impl HelperDef for RenderToc {
 
             if level > current_level {
                 while level > current_level {
-                    rc.writer.write_all(b"<li>")?;
-                    rc.writer.write_all(b"<ol class=\"section\">")?;
+                    out.write("<li>")?;
+                    out.write("<ol class=\"section\">")?;
                     current_level += 1;
                 }
-                rc.writer.write_all(b"<li>")?;
+                out.write("<li>")?;
             } else if level < current_level {
                 while level < current_level {
-                    rc.writer.write_all(b"</ol>")?;
-                    rc.writer.write_all(b"</li>")?;
+                    out.write("</ol>")?;
+                    out.write("</li>")?;
                     current_level -= 1;
                 }
-                rc.writer.write_all(b"<li>")?;
+                out.write("<li>")?;
             } else {
-                rc.writer.write_all(b"<li")?;
+                out.write("<li")?;
                 if item.get("section").is_none() {
-                    rc.writer.write_all(b" class=\"affix\"")?;
+                    out.write(" class=\"affix\"")?;
                 }
-                rc.writer.write_all(b">")?;
+                out.write(">")?;
             }
 
             // Link
             let path_exists = if let Some(path) = item.get("path") {
                 if !path.is_empty() {
-                    rc.writer.write_all(b"<a href=\"")?;
+                    out.write("<a href=\"")?;
 
                     let tmp = Path::new(item.get("path").expect("Error: path should be Some(_)"))
                         .with_extension("html")
@@ -79,16 +87,15 @@ impl HelperDef for RenderToc {
                         .replace("\\", "/");
 
                     // Add link
-                    rc.writer
-                        .write_all(&utils::fs::path_to_root(&current).as_bytes())?;
-                    rc.writer.write_all(tmp.as_bytes())?;
-                    rc.writer.write_all(b"\"")?;
+                    out.write(&utils::fs::path_to_root(&current))?;
+                    out.write(&tmp)?;
+                    out.write("\"")?;
 
                     if path == &current {
-                        rc.writer.write_all(b" class=\"active\"")?;
+                        out.write(" class=\"active\"")?;
                     }
 
-                    rc.writer.write_all(b">")?;
+                    out.write(">")?;
                     true
                 } else {
                     false
@@ -100,9 +107,9 @@ impl HelperDef for RenderToc {
             if !self.no_section_label {
                 // Section does not necessarily exist
                 if let Some(section) = item.get("section") {
-                    rc.writer.write_all(b"<strong aria-hidden=\"true\">")?;
-                    rc.writer.write_all(section.as_bytes())?;
-                    rc.writer.write_all(b"</strong> ")?;
+                    out.write("<strong aria-hidden=\"true\">")?;
+                    out.write(&section)?;
+                    out.write("</strong> ")?;
                 }
             }
 
@@ -123,22 +130,22 @@ impl HelperDef for RenderToc {
                 html::push_html(&mut markdown_parsed_name, parser);
 
                 // write to the handlebars template
-                rc.writer.write_all(markdown_parsed_name.as_bytes())?;
+                out.write(&markdown_parsed_name)?;
             }
 
             if path_exists {
-                rc.writer.write_all(b"</a>")?;
+                out.write("</a>")?;
             }
 
-            rc.writer.write_all(b"</li>")?;
+            out.write("</li>")?;
         }
         while current_level > 1 {
-            rc.writer.write_all(b"</ol>")?;
-            rc.writer.write_all(b"</li>")?;
+            out.write("</ol>")?;
+            out.write("</li>")?;
             current_level -= 1;
         }
 
-        rc.writer.write_all(b"</ol>")?;
+        out.write("</ol>")?;
         Ok(())
     }
 }

src/renderer/html_handlebars/search.rs

@@ -54,7 +54,7 @@ fn add_doc(
     section_id: &Option<String>,
     items: &[&str],
 ) {
-    let url = if let &Some(ref id) = section_id {
+    let url = if let Some(ref id) = *section_id {
         Cow::Owned(format!("{}#{}", anchor_base, id))
     } else {
         Cow::Borrowed(anchor_base)
@@ -74,8 +74,8 @@ fn render_item(
     doc_urls: &mut Vec<String>,
     item: &BookItem,
 ) -> Result<()> {
-    let chapter = match item {
-        &BookItem::Chapter(ref ch) => ch,
+    let chapter = match *item {
+        BookItem::Chapter(ref ch) => ch,
         _ => return Ok(()),
     };
 
@@ -101,7 +101,7 @@ fn render_item(
     for event in p {
         match event {
             Event::Start(Tag::Header(i)) if i <= max_section_depth => {
-                if heading.len() > 0 {
+                if !heading.is_empty() {
                     // Section finished, the next header is following now
                     // Write the data to the index, and clear it for the next section
                     add_doc(
@@ -155,7 +155,7 @@ fn render_item(
         }
     }
 
-    if heading.len() > 0 {
+    if !heading.is_empty() {
         // Make sure the last section is added to the index
         add_doc(
             index,

src/renderer/mod.rs

@@ -8,7 +8,7 @@
 //!
 //! The definition for [RenderContext] may be useful though.
 //!
-//! [For Developers]: https://rust-lang-nursery.github.io/mdBook/lib/index.html
+//! [For Developers]: https://rust-lang-nursery.github.io/mdBook/for_developers/index.html
 //! [RenderContext]: struct.RenderContext.html
 
 pub use self::html_handlebars::HtmlHandlebars;
@@ -26,8 +26,6 @@ use book::Book;
 use config::Config;
 use errors::*;
 
-const MDBOOK_VERSION: &str = env!("CARGO_PKG_VERSION");
-
 /// An arbitrary `mdbook` backend.
 ///
 /// Although it's quite possible for you to import `mdbook` as a library and
@@ -66,6 +64,8 @@ pub struct RenderContext {
     /// renderers to cache intermediate results, this directory is not
     /// guaranteed to be empty or even exist.
     pub destination: PathBuf,
+    #[serde(skip)]
+    __non_exhaustive: (),
 }
 
 impl RenderContext {
@@ -76,11 +76,12 @@ impl RenderContext {
         Q: Into<PathBuf>,
     {
         RenderContext {
-            book: book,
-            config: config,
-            version: MDBOOK_VERSION.to_string(),
+            book,
+            config,
+            version: ::MDBOOK_VERSION.to_string(),
             root: root.into(),
             destination: destination.into(),
+            __non_exhaustive: (),
         }
     }
 
@@ -157,7 +158,8 @@ impl Renderer for CmdRenderer {
 
         let _ = fs::create_dir_all(&ctx.destination);
 
-        let mut child = match self.compose_command()?
+        let mut child = match self
+            .compose_command()?
             .stdin(Stdio::piped())
             .stdout(Stdio::inherit())
             .stderr(Stdio::inherit())

src/theme/book.js

@@ -352,7 +352,7 @@ function playpen_text(playpen) {
 
         var previousTheme;
         try { previousTheme = localStorage.getItem('mdbook-theme'); } catch (e) { }
-        if (previousTheme === null || previousTheme === undefined) { previousTheme = 'light'; }
+        if (previousTheme === null || previousTheme === undefined) { previousTheme = default_theme; }
 
         try { localStorage.setItem('mdbook-theme', theme); } catch (e) { }
 
@@ -364,7 +364,7 @@ function playpen_text(playpen) {
     // Set theme
     var theme;
     try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
-    if (theme === null || theme === undefined) { theme = 'light'; }
+    if (theme === null || theme === undefined) { theme = default_theme; }
 
     set_theme(theme);
 

src/theme/css/chrome.css

@@ -63,9 +63,12 @@ a > .hljs {
     margin: 0;
 }
 
-#print-button {
+.right-buttons {
     margin: 0 15px;
 }
+.right-buttons a {
+    text-decoration: none;
+}
 
 html:not(.sidebar-visible) #menu-bar:not(:hover).folded > #menu-bar-sticky-container {
     transform: translateY(-60px);

src/theme/css/variables.css

@@ -10,7 +10,7 @@
 /* Themes */
 
 .ayu {
-    --bg: #0f1419;
+    --bg: hsl(210, 25%, 8%);
     --fg: #c5c5c5;
 
     --sidebar-bg: #14191f;
@@ -32,12 +32,12 @@
     --theme-popup-border: #5c6773;
     --theme-hover: #191f26;
 
-    --quote-bg: #262933;
-    --quote-border: lighten(var(--quote-bg), 5%);
+    --quote-bg: hsl(226, 15%, 17%);
+    --quote-border: hsl(226, 15%, 22%);
 
-    --table-border-color: lighten(var(--bg), 5%);
-    --table-header-bg: lighten(var(--bg), 20%);
-    --table-alternate-bg: lighten(var(--bg), 3%);
+    --table-border-color: hsl(210, 25%, 13%);
+    --table-header-bg: hsl(210, 25%, 28%);
+    --table-alternate-bg: hsl(210, 25%, 11%);
 
     --searchbar-border-color: #848484;
     --searchbar-bg: #424242;
@@ -50,7 +50,7 @@
 }
 
 .coal {
-    --bg: #141617;
+    --bg: hsl(200, 7%, 8%);
     --fg: #98a3ad;
 
     --sidebar-bg: #292c2f;
@@ -72,12 +72,12 @@
     --theme-popup-border: #43484d;
     --theme-hover: #1f2124;
 
-    --quote-bg: #242637;
-    --quote-border: lighten(var(--quote-bg), 5%);
+    --quote-bg: hsl(234, 21%, 18%);
+    --quote-border: hsl(234, 21%, 23%);
 
-    --table-border-color: lighten(var(--bg), 5%);
-    --table-header-bg: lighten(var(--bg), 20%);
-    --table-alternate-bg: lighten(var(--bg), 3%);
+    --table-border-color: hsl(200, 7%, 13%);
+    --table-header-bg: hsl(200, 7%, 28%);
+    --table-alternate-bg: hsl(200, 7%, 11%);
 
     --searchbar-border-color: #aaa;
     --searchbar-bg: #b7b7b7;
@@ -90,7 +90,7 @@
 }
 
 .light {
-    --bg: #ffffff;
+    --bg: hsl(0, 0%, 100%);
     --fg: #333333;
 
     --sidebar-bg: #fafafa;
@@ -112,12 +112,12 @@
     --theme-popup-border: #cccccc;
     --theme-hover: #e6e6e6;
 
-    --quote-bg: #f2f7f9;
-    --quote-border: darken(var(--quote-bg), 5%);
+    --quote-bg: hsl(197, 37%, 96%);
+    --quote-border: hsl(197, 37%, 91%);
 
-    --table-border-color: darken(var(--bg), 5%);
-    --table-header-bg: darken(var(--bg), 20%);
-    --table-alternate-bg: darken(var(--bg), 3%);
+    --table-border-color: hsl(0, 0%, 95%);
+    --table-header-bg: hsl(0, 0%, 80%);
+    --table-alternate-bg: hsl(0, 0%, 97%);
 
     --searchbar-border-color: #aaa;
     --searchbar-bg: #fafafa;
@@ -130,7 +130,7 @@
 }
 
 .navy {
-    --bg: #161923;
+    --bg: hsl(226, 23%, 11%);
     --fg: #bcbdd0;
 
     --sidebar-bg: #282d3f;
@@ -152,12 +152,12 @@
     --theme-popup-border: #737480;
     --theme-hover: #282e40;
 
-    --quote-bg: #262933;
-    --quote-border: lighten(var(--quote-bg), 5%);
+    --quote-bg: hsl(226, 15%, 17%);
+    --quote-border: hsl(226, 15%, 22%);
 
-    --table-border-color: lighten(var(--bg), 5%);
-    --table-header-bg: lighten(var(--bg), 20%);
-    --table-alternate-bg: lighten(var(--bg), 3%);
+    --table-border-color: hsl(226, 23%, 16%);
+    --table-header-bg: hsl(226, 23%, 31%);
+    --table-alternate-bg: hsl(226, 23%, 14%);
 
     --searchbar-border-color: #aaa;
     --searchbar-bg: #aeaec6;
@@ -170,7 +170,7 @@
 }
 
 .rust {
-    --bg: #e1e1db;
+    --bg: hsl(60, 9%, 87%);
     --fg: #262625;
 
     --sidebar-bg: #3b2e2a;
@@ -192,12 +192,12 @@
     --theme-popup-border: #b38f6b;
     --theme-hover: #99908a;
 
-    --quote-bg: #c1c1bb;
-    --quote-border: darken(var(--quote-bg), 5%);
+    --quote-bg: hsl(60, 5%, 75%);
+    --quote-border: hsl(60, 5%, 70%);
 
-    --table-border-color: darken(var(--bg), 5%);
+    --table-border-color: hsl(60, 9%, 82%);
     --table-header-bg: #b3a497;
-    --table-alternate-bg: darken(var(--bg), 3%);
+    --table-alternate-bg: hsl(60, 9%, 84%);
 
     --searchbar-border-color: #aaa;
     --searchbar-bg: #fafafa;

src/theme/index.hbs

@@ -27,7 +27,7 @@
 
         <!-- Custom theme stylesheets -->
         {{#each additional_css}}
-        <link rel="stylesheet" href="{{ this }}">
+        <link rel="stylesheet" href="{{ ../path_to_root }}{{ this }}">
         {{/each}}
 
         {{#if mathjax_support}}
@@ -35,9 +35,12 @@
         <script async type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
         {{/if}}
     </head>
-    <body class="light">
+    <body class="{{ default_theme }}">
         <!-- Provide site root to javascript -->
-        <script type="text/javascript">var path_to_root = "{{ path_to_root }}";</script>
+        <script type="text/javascript">
+            var path_to_root = "{{ path_to_root }}";
+            var default_theme = "{{ default_theme }}";
+        </script>
 
         <!-- Work around some values being stored in localStorage wrapped in quotes -->
         <script type="text/javascript">
@@ -59,7 +62,7 @@
         <script type="text/javascript">
             var theme;
             try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { } 
-            if (theme === null || theme === undefined) { theme = 'light'; }
+            if (theme === null || theme === undefined) { theme = default_theme; }
             document.body.className = theme;
             document.querySelector('html').className = theme + ' js';
         </script>
@@ -94,11 +97,11 @@
                                 <i class="fa fa-paint-brush"></i>
                             </button>
                             <ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
-                                <li role="none"><button role="menuitem" class="theme" id="light">Light <span class="default">(default)</span></button></li>
-                                <li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
-                                <li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
-                                <li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
-                                <li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
+                                <li role="none"><button role="menuitem" class="theme" id="light">{{ theme_option "Light" }}</button></li>
+                                <li role="none"><button role="menuitem" class="theme" id="rust">{{ theme_option "Rust" }}</button></li>
+                                <li role="none"><button role="menuitem" class="theme" id="coal">{{ theme_option "Coal" }}</button></li>
+                                <li role="none"><button role="menuitem" class="theme" id="navy">{{ theme_option "Navy" }}</button></li>
+                                <li role="none"><button role="menuitem" class="theme" id="ayu">{{ theme_option "Ayu" }}</button></li>
                             </ul>
                             {{#if search_enabled}}
                             <button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
@@ -113,6 +116,11 @@
                             <a href="{{ path_to_root }}print.html" title="Print this book" aria-label="Print this book">
                                 <i id="print-button" class="fa fa-print"></i>
                             </a>
+                            {{#if git_repository_url}}
+                            <a href="{{git_repository_url}}" title="Git repository" aria-label="Git repository">
+                                <i id="git-repository-button" class="fa {{git_repository_icon}}"></i>
+                            </a>
+                            {{/if}}
                         </div>
                     </div>
                 </div>
@@ -235,7 +243,7 @@
 
         <!-- Custom JS scripts -->
         {{#each additional_js}}
-        <script type="text/javascript" src="{{ path_to_root }}{{this}}"></script>
+        <script type="text/javascript" src="{{ ../path_to_root }}{{this}}"></script>
         {{/each}}
 
         {{#if is_print}}

src/utils/mod.rs

@@ -21,9 +21,10 @@ pub fn collapse_whitespace<'a>(text: &'a str) -> Cow<'a, str> {
     RE.replace_all(text, " ")
 }
 
-/// Convert the given string to a valid HTML element ID
+/// Convert the given string to a valid HTML element ID.
+/// The only restriction is that the ID must not contain any ASCII whitespace.
 pub fn normalize_id(content: &str) -> String {
-    let mut ret = content
+    content
         .chars()
         .filter_map(|ch| {
             if ch.is_alphanumeric() || ch == '_' || ch == '-' {
@@ -33,16 +34,7 @@ pub fn normalize_id(content: &str) -> String {
             } else {
                 None
             }
-        })
-        .collect::<String>();
-    // Ensure that the first character is [A-Za-z]
-    if ret.chars()
-        .next()
-        .map_or(false, |c| !c.is_ascii_alphabetic())
-    {
-        ret.insert(0, 'a');
-    }
-    ret
+        }).collect::<String>()
 }
 
 /// Generate an ID for use with anchors which is derived from a "normalised"
@@ -74,15 +66,21 @@ pub fn id_from_content(content: &str) -> String {
     normalize_id(trimmed)
 }
 
-fn adjust_links(event: Event) -> Event {
+fn adjust_links<'a>(event: Event<'a>, with_base: &str) -> Event<'a> {
     lazy_static! {
         static ref HTTP_LINK: Regex = Regex::new("^https?://").unwrap();
-        static ref MD_LINK: Regex = Regex::new("(?P<link>.*).md(?P<anchor>#.*)?").unwrap();
+        static ref MD_LINK: Regex = Regex::new(r"(?P<link>.*)\.md(?P<anchor>#.*)?").unwrap();
     }
 
     match event {
         Event::Start(Tag::Link(dest, title)) => {
             if !HTTP_LINK.is_match(&dest) {
+                let dest = if !with_base.is_empty() {
+                    format!("{}/{}", with_base, dest)
+                } else {
+                    dest.clone().into_owned()
+                };
+
                 if let Some(caps) = MD_LINK.captures(&dest) {
                     let mut html_link = [&caps["link"], ".html"].concat();
 
@@ -102,6 +100,10 @@ fn adjust_links(event: Event) -> Event {
 
 /// Wrapper around the pulldown-cmark parser for rendering markdown to HTML.
 pub fn render_markdown(text: &str, curly_quotes: bool) -> String {
+    render_markdown_with_base(text, curly_quotes, "")
+}
+
+pub fn render_markdown_with_base(text: &str, curly_quotes: bool, base: &str) -> String {
     let mut s = String::with_capacity(text.len() * 3 / 2);
 
     let mut opts = Options::empty();
@@ -110,8 +112,9 @@ pub fn render_markdown(text: &str, curly_quotes: bool) -> String {
 
     let p = Parser::new_ext(text, opts);
     let mut converter = EventQuoteConverter::new(curly_quotes);
-    let events = p.map(clean_codeblock_headers)
-        .map(adjust_links)
+    let events = p
+        .map(clean_codeblock_headers)
+        .map(|event| adjust_links(event, base))
         .map(|event| converter.convert(event));
 
     html::push_html(&mut s, events);
@@ -126,7 +129,7 @@ struct EventQuoteConverter {
 impl EventQuoteConverter {
     fn new(enabled: bool) -> Self {
         EventQuoteConverter {
-            enabled: enabled,
+            enabled,
             convert_text: true,
         }
     }
@@ -192,8 +195,7 @@ fn convert_quotes_to_curly(original_text: &str) -> String {
             preceded_by_whitespace = original_char.is_whitespace();
 
             converted_char
-        })
-        .collect()
+        }).collect()
 }
 
 /// Prints a "backtrace" of some `Error`.
@@ -228,6 +230,12 @@ mod tests {
                 render_markdown("[example_anchor](example.md#anchor)", false),
                 "<p><a href=\"example.html#anchor\">example_anchor</a></p>\n"
             );
+
+            // this anchor contains 'md' inside of it
+            assert_eq!(
+                render_markdown("[phantom data](foo.html#phantomdata)", false),
+                "<p><a href=\"foo.html#phantomdata\">phantom data</a></p>\n"
+            );
         }
 
         #[test]
@@ -328,28 +336,42 @@ more text with spaces
 
         #[test]
         fn it_generates_anchors() {
-            assert_eq!(
-                id_from_content("## `--passes`: add more rustdoc passes"),
-                "a--passes-add-more-rustdoc-passes"
-            );
             assert_eq!(
                 id_from_content("## Method-call expressions"),
                 "method-call-expressions"
             );
+            assert_eq!(id_from_content("## **Bold** title"), "bold-title");
+            assert_eq!(id_from_content("## `Code` title"), "code-title");
+        }
+
+        #[test]
+        fn it_generates_anchors_from_non_ascii_initial() {
+            assert_eq!(
+                id_from_content("## `--passes`: add more rustdoc passes"),
+                "--passes-add-more-rustdoc-passes"
+            );
+            assert_eq!(
+                id_from_content("## 中文標題 CJK title"),
+                "中文標題-cjk-title"
+            );
+            assert_eq!(id_from_content("## Über"), "Über");
         }
 
         #[test]
         fn it_normalizes_ids() {
             assert_eq!(
                 normalize_id("`--passes`: add more rustdoc passes"),
-                "a--passes-add-more-rustdoc-passes"
+                "--passes-add-more-rustdoc-passes"
             );
             assert_eq!(
                 normalize_id("Method-call 🐙 expressions \u{1f47c}"),
                 "method-call--expressions-"
             );
-            assert_eq!(normalize_id("_-_12345"), "a_-_12345");
-            assert_eq!(normalize_id("12345"), "a12345");
+            assert_eq!(normalize_id("_-_12345"), "_-_12345");
+            assert_eq!(normalize_id("12345"), "12345");
+            assert_eq!(normalize_id("中文"), "中文");
+            assert_eq!(normalize_id("にほんご"), "にほんご");
+            assert_eq!(normalize_id("한국어"), "한국어");
             assert_eq!(normalize_id(""), "");
         }
     }

tests/alternate_backends.rs

@@ -11,14 +11,14 @@ use tempfile::{Builder as TempFileBuilder, TempDir};
 
 #[test]
 fn passing_alternate_backend() {
-    let (md, _temp) = dummy_book_with_backend("passing", "true");
+    let (md, _temp) = dummy_book_with_backend("passing", success_cmd());
 
     md.build().unwrap();
 }
 
 #[test]
 fn failing_alternate_backend() {
-    let (md, _temp) = dummy_book_with_backend("failing", "false");
+    let (md, _temp) = dummy_book_with_backend("failing", fail_cmd());
 
     md.build().unwrap_err();
 }
@@ -84,3 +84,19 @@ fn dummy_book_with_backend(name: &str, command: &str) -> (MDBook, TempDir) {
 
     (md, temp)
 }
+
+fn fail_cmd() -> &'static str {
+    if cfg!(windows) {
+        r#"cmd.exe /c "exit 1""#
+    } else {
+        "false"
+    }
+}
+
+fn success_cmd() -> &'static str {
+    if cfg!(windows) {
+        r#"cmd.exe /c "exit 0""#
+    } else {
+        "true"
+    }
+}

tests/build_process.rs

@@ -0,0 +1,80 @@
+extern crate mdbook;
+
+mod dummy_book;
+
+use dummy_book::DummyBook;
+use mdbook::book::Book;
+use mdbook::config::Config;
+use mdbook::errors::*;
+use mdbook::preprocess::{Preprocessor, PreprocessorContext};
+use mdbook::renderer::{RenderContext, Renderer};
+use mdbook::MDBook;
+use std::sync::{Arc, Mutex};
+
+struct Spy(Arc<Mutex<Inner>>);
+
+#[derive(Debug, Default)]
+struct Inner {
+    run_count: usize,
+    rendered_with: Vec<String>,
+}
+
+impl Preprocessor for Spy {
+    fn name(&self) -> &str {
+        "dummy"
+    }
+
+    fn run(&self, ctx: &PreprocessorContext, book: Book) -> Result<Book> {
+        let mut inner = self.0.lock().unwrap();
+        inner.run_count += 1;
+        inner.rendered_with.push(ctx.renderer.clone());
+        Ok(book)
+    }
+}
+
+impl Renderer for Spy {
+    fn name(&self) -> &str {
+        "dummy"
+    }
+
+    fn render(&self, _ctx: &RenderContext) -> Result<()> {
+        let mut inner = self.0.lock().unwrap();
+        inner.run_count += 1;
+        Ok(())
+    }
+}
+
+#[test]
+fn mdbook_runs_preprocessors() {
+    let spy: Arc<Mutex<Inner>> = Default::default();
+
+    let temp = DummyBook::new().build().unwrap();
+    let cfg = Config::default();
+
+    let mut book = MDBook::load_with_config(temp.path(), cfg).unwrap();
+    book.with_preprecessor(Spy(Arc::clone(&spy)));
+    book.build().unwrap();
+
+    let inner = spy.lock().unwrap();
+    assert_eq!(inner.run_count, 1);
+    assert_eq!(inner.rendered_with.len(), 1);
+    assert_eq!(
+        "html", inner.rendered_with[0],
+        "We should have been run with the default HTML renderer"
+    );
+}
+
+#[test]
+fn mdbook_runs_renderers() {
+    let spy: Arc<Mutex<Inner>> = Default::default();
+
+    let temp = DummyBook::new().build().unwrap();
+    let cfg = Config::default();
+
+    let mut book = MDBook::load_with_config(temp.path(), cfg).unwrap();
+    book.with_renderer(Spy(Arc::clone(&spy)));
+    book.build().unwrap();
+
+    let inner = spy.lock().unwrap();
+    assert_eq!(inner.run_count, 1);
+}

tests/custom_preprocessors.rs

@@ -0,0 +1,58 @@
+extern crate mdbook;
+
+mod dummy_book;
+
+use dummy_book::DummyBook;
+use mdbook::preprocess::{CmdPreprocessor, Preprocessor};
+use mdbook::MDBook;
+
+fn example() -> CmdPreprocessor {
+    CmdPreprocessor::new(
+        "nop-preprocessor".to_string(),
+        "cargo run --example nop-preprocessor --".to_string(),
+    )
+}
+
+#[test]
+fn example_supports_whatever() {
+    let cmd = example();
+
+    let got = cmd.supports_renderer("whatever");
+
+    assert_eq!(got, true);
+}
+
+#[test]
+fn example_doesnt_support_not_supported() {
+    let cmd = example();
+
+    let got = cmd.supports_renderer("not-supported");
+
+    assert_eq!(got, false);
+}
+
+#[test]
+fn ask_the_preprocessor_to_blow_up() {
+    let dummy_book = DummyBook::new();
+    let temp = dummy_book.build().unwrap();
+    let mut md = MDBook::load(temp.path()).unwrap();
+    md.with_preprecessor(example());
+
+    md.config
+        .set("preprocessor.nop-preprocessor.blow-up", true)
+        .unwrap();
+
+    let got = md.build();
+
+    assert!(got.is_err());
+}
+
+#[test]
+fn process_the_dummy_book() {
+    let dummy_book = DummyBook::new();
+    let temp = dummy_book.build().unwrap();
+    let mut md = MDBook::load(temp.path()).unwrap();
+    md.with_preprecessor(example());
+
+    md.build().unwrap();
+}

tests/dummy_book/src/SUMMARY.md

@@ -8,6 +8,7 @@
     - [Includes](first/includes.md)
     - [Recursive](first/recursive.md)
 - [Second Chapter](second.md)
+    - [Nested Chapter](second/nested.md)
 
 ---
 

tests/dummy_book/src/second/nested.md

@@ -0,0 +1,4 @@
+# Testing relative links for the print page
+
+When we link to [the first section](../first/nested.md), it should work on
+both the print page and the non-print page.

tests/rendered_output.rs

@@ -31,7 +31,7 @@ const TOC_TOP_LEVEL: &[&'static str] = &[
     "Introduction",
 ];
 const TOC_SECOND_LEVEL: &[&'static str] =
-    &["1.1. Nested Chapter", "1.2. Includes", "1.3. Recursive"];
+    &["1.1. Nested Chapter", "1.2. Includes", "2.1. Nested Chapter", "1.3. Recursive"];
 
 /// Make sure you can load the dummy book and build it without panicking.
 #[test]
@@ -109,6 +109,20 @@ fn check_correct_cross_links_in_nested_dir() {
     );
 }
 
+#[test]
+fn check_correct_relative_links_in_print_page() {
+    let temp = DummyBook::new().build().unwrap();
+    let md = MDBook::load(temp.path()).unwrap();
+    md.build().unwrap();
+
+    let first = temp.path().join("book");
+
+    assert_contains_strings(
+        first.join("print.html"),
+        &[r##"<a href="second/../first/nested.html">the first section</a>,"##],
+    );
+}
+
 #[test]
 fn rendered_code_has_playpen_stuff() {
     let temp = DummyBook::new().build().unwrap();
@@ -174,7 +188,8 @@ fn chapter_files_were_rendered_to_html() {
         .filter(|path| path.file_name().and_then(OsStr::to_str) != Some("SUMMARY.md"));
 
     for chapter in chapter_files {
-        let rendered_location = temp.path()
+        let rendered_location = temp
+            .path()
             .join(chapter.strip_prefix(&src).unwrap())
             .with_extension("html");
         assert!(
@@ -213,7 +228,8 @@ fn check_second_toc_level() {
 
     let pred = descendants!(Class("chapter"), Name("li"), Name("li"), Name("a"));
 
-    let mut children_of_children: Vec<_> = doc.find(pred)
+    let mut children_of_children: Vec<_> = doc
+        .find(pred)
         .map(|elem| elem.text().trim().to_string())
         .collect();
     children_of_children.sort();
@@ -231,7 +247,8 @@ fn check_first_toc_level() {
 
     let pred = descendants!(Class("chapter"), Name("li"), Name("a"));
 
-    let mut children: Vec<_> = doc.find(pred)
+    let mut children: Vec<_> = doc
+        .find(pred)
         .map(|elem| elem.text().trim().to_string())
         .collect();
     children.sort();
@@ -244,7 +261,8 @@ fn check_spacers() {
     let doc = root_index_html().unwrap();
     let should_be = 1;
 
-    let num_spacers = doc.find(Class("chapter").descendant(Name("li").and(Class("spacer"))))
+    let num_spacers = doc
+        .find(Class("chapter").descendant(Name("li").and(Class("spacer"))))
         .count();
     assert_eq!(num_spacers, should_be);
 }
@@ -439,7 +457,7 @@ mod search {
         assert_eq!(docs[&some_section]["body"], "");
         assert_eq!(
             docs[&summary]["body"],
-            "Dummy Book Introduction First Chapter Nested Chapter Includes Recursive Second Chapter Conclusion"
+            "Dummy Book Introduction First Chapter Nested Chapter Includes Recursive Second Chapter Nested Chapter Conclusion"
         );
         assert_eq!(docs[&summary]["breadcrumbs"], "First Chapter » Summary");
         assert_eq!(docs[&conclusion]["body"], "I put &lt;HTML&gt; in here!");

tests/searchindex_fixture.json

@@ -9,6 +9,7 @@
     "first/includes.html#includes",
     "first/includes.html#summary",
     "second.html#second-chapter",
+    "second/nested.html#testing-relative-links-for-the-print-page",
     "conclusion.html#conclusion"
   ],
   "index": {
@@ -24,6 +25,11 @@
           "breadcrumbs": 1,
           "title": 1
         },
+        "10": {
+          "body": 3,
+          "breadcrumbs": 1,
+          "title": 1
+        },
         "2": {
           "body": 2,
           "breadcrumbs": 2,
@@ -50,7 +56,7 @@
           "title": 1
         },
         "7": {
-          "body": 12,
+          "body": 14,
           "breadcrumbs": 3,
           "title": 1
         },
@@ -60,9 +66,9 @@
           "title": 2
         },
         "9": {
-          "body": 3,
-          "breadcrumbs": 1,
-          "title": 1
+          "body": 10,
+          "breadcrumbs": 7,
+          "title": 5
         }
       },
       "docs": {
@@ -78,6 +84,12 @@
           "id": "1",
           "title": "Introduction"
         },
+        "10": {
+          "body": "I put <HTML> in here!",
+          "breadcrumbs": "Conclusion",
+          "id": "10",
+          "title": "Conclusion"
+        },
         "2": {
           "body": "more text.",
           "breadcrumbs": "First Chapter",
@@ -109,7 +121,7 @@
           "title": "Includes"
         },
         "7": {
-          "body": "Dummy Book Introduction First Chapter Nested Chapter Includes Recursive Second Chapter Conclusion",
+          "body": "Dummy Book Introduction First Chapter Nested Chapter Includes Recursive Second Chapter Nested Chapter Conclusion",
           "breadcrumbs": "First Chapter » Summary",
           "id": "7",
           "title": "Summary"
@@ -121,13 +133,13 @@
           "title": "Second Chapter"
         },
         "9": {
-          "body": "I put <HTML> in here!",
-          "breadcrumbs": "Conclusion",
+          "body": "When we link to the first section , it should work on both the print page and the non-print page.",
+          "breadcrumbs": "Second Chapter » Testing relative links for the print page",
           "id": "9",
-          "title": "Conclusion"
+          "title": "Testing relative links for the print page"
         }
       },
-      "length": 10,
+      "length": 11,
       "save": true
     },
     "fields": [
@@ -206,6 +218,18 @@
                     }
                   }
                 }
+              },
+              "t": {
+                "df": 0,
+                "docs": {},
+                "h": {
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 1.0
+                    }
+                  }
+                }
               }
             }
           },
@@ -251,7 +275,7 @@
                             "tf": 1.0
                           },
                           "7": {
-                            "tf": 1.7320508075688773
+                            "tf": 2.0
                           },
                           "8": {
                             "tf": 1.0
@@ -296,10 +320,10 @@
                       "s": {
                         "df": 2,
                         "docs": {
-                          "7": {
+                          "10": {
                             "tf": 1.0
                           },
-                          "9": {
+                          "7": {
                             "tf": 1.0
                           }
                         }
@@ -420,13 +444,16 @@
                   "df": 0,
                   "docs": {},
                   "t": {
-                    "df": 2,
+                    "df": 3,
                     "docs": {
                       "2": {
                         "tf": 1.0
                       },
                       "7": {
                         "tf": 1.0
+                      },
+                      "9": {
+                        "tf": 1.0
                       }
                     }
                   }
@@ -485,7 +512,7 @@
                     "0": {
                       "tf": 1.0
                     },
-                    "9": {
+                    "10": {
                       "tf": 1.0
                     }
                   }
@@ -683,6 +710,14 @@
                       "tf": 1.0
                     }
                   }
+                },
+                "k": {
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 1.4142135623730951
+                    }
+                  }
                 }
               }
             },
@@ -709,7 +744,7 @@
                             "t": {
                               "df": 1,
                               "docs": {
-                                "9": {
+                                "10": {
                                   "tf": 1.0
                                 }
                               }
@@ -791,14 +826,42 @@
                       "tf": 1.0
                     },
                     "7": {
-                      "tf": 1.0
+                      "tf": 1.4142135623730951
                     }
                   }
                 }
               }
+            },
+            "o": {
+              "df": 0,
+              "docs": {},
+              "n": {
+                "df": 1,
+                "docs": {
+                  "9": {
+                    "tf": 1.0
+                  }
+                }
+              }
             }
           },
           "p": {
+            "a": {
+              "df": 0,
+              "docs": {},
+              "g": {
+                "df": 0,
+                "docs": {},
+                "e": {
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 1.7320508075688772
+                    }
+                  }
+                }
+              }
+            },
             "df": 0,
             "docs": {},
             "r": {
@@ -871,8 +934,12 @@
                   "df": 0,
                   "docs": {},
                   "t": {
-                    "df": 0,
-                    "docs": {},
+                    "df": 1,
+                    "docs": {
+                      "9": {
+                        "tf": 1.7320508075688772
+                      }
+                    },
                     "l": {
                       "df": 0,
                       "docs": {},
@@ -935,7 +1002,7 @@
               "t": {
                 "df": 1,
                 "docs": {
-                  "9": {
+                  "10": {
                     "tf": 1.0
                   }
                 }
@@ -967,7 +1034,15 @@
                 }
               },
               "df": 0,
-              "docs": {}
+              "docs": {},
+              "l": {
+                "df": 1,
+                "docs": {
+                  "9": {
+                    "tf": 1.0
+                  }
+                }
+              }
             },
             "u": {
               "df": 0,
@@ -1050,13 +1125,16 @@
                       "df": 0,
                       "docs": {},
                       "n": {
-                        "df": 2,
+                        "df": 3,
                         "docs": {
                           "3": {
                             "tf": 1.0
                           },
                           "5": {
                             "tf": 1.0
+                          },
+                          "9": {
+                            "tf": 1.0
                           }
                         }
                       }
@@ -1170,8 +1248,12 @@
                     "df": 0,
                     "docs": {}
                   },
-                  "df": 0,
-                  "docs": {}
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 1.0
+                    }
+                  }
                 }
               },
               "x": {
@@ -1200,6 +1282,14 @@
               "r": {
                 "df": 0,
                 "docs": {},
+                "k": {
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 1.0
+                    }
+                  }
+                },
                 "l": {
                   "d": {
                     "df": 1,
@@ -1280,13 +1370,25 @@
                   "df": 2,
                   "docs": {
                     "0": {
-                      "tf": 1.4142135623730952
+                      "tf": 1.4142135623730951
                     },
                     "7": {
                       "tf": 1.0
                     }
                   }
                 }
+              },
+              "t": {
+                "df": 0,
+                "docs": {},
+                "h": {
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 1.0
+                    }
+                  }
+                }
               }
             }
           },
@@ -1323,13 +1425,13 @@
                       "df": 0,
                       "docs": {},
                       "r": {
-                        "df": 6,
+                        "df": 7,
                         "docs": {
                           "2": {
-                            "tf": 1.4142135623730952
+                            "tf": 1.4142135623730951
                           },
                           "4": {
-                            "tf": 1.7320508075688773
+                            "tf": 1.7320508075688772
                           },
                           "5": {
                             "tf": 1.0
@@ -1338,10 +1440,13 @@
                             "tf": 1.0
                           },
                           "7": {
-                            "tf": 2.0
+                            "tf": 2.23606797749979
                           },
                           "8": {
-                            "tf": 1.4142135623730952
+                            "tf": 1.4142135623730951
+                          },
+                          "9": {
+                            "tf": 1.0
                           }
                         }
                       }
@@ -1383,11 +1488,11 @@
                       "s": {
                         "df": 2,
                         "docs": {
+                          "10": {
+                            "tf": 1.4142135623730951
+                          },
                           "7": {
                             "tf": 1.0
-                          },
-                          "9": {
-                            "tf": 1.4142135623730952
                           }
                         }
                       }
@@ -1419,7 +1524,7 @@
                     "df": 2,
                     "docs": {
                       "0": {
-                        "tf": 1.4142135623730952
+                        "tf": 1.4142135623730951
                       },
                       "7": {
                         "tf": 1.0
@@ -1507,10 +1612,10 @@
                   "df": 0,
                   "docs": {},
                   "t": {
-                    "df": 5,
+                    "df": 6,
                     "docs": {
                       "2": {
-                        "tf": 1.4142135623730952
+                        "tf": 1.4142135623730951
                       },
                       "4": {
                         "tf": 1.0
@@ -1522,7 +1627,10 @@
                         "tf": 1.0
                       },
                       "7": {
-                        "tf": 1.4142135623730952
+                        "tf": 1.4142135623730951
+                      },
+                      "9": {
+                        "tf": 1.0
                       }
                     }
                   }
@@ -1581,7 +1689,7 @@
                     "0": {
                       "tf": 1.0
                     },
-                    "9": {
+                    "10": {
                       "tf": 1.0
                     }
                   }
@@ -1636,7 +1744,7 @@
                       "df": 2,
                       "docs": {
                         "6": {
-                          "tf": 1.4142135623730952
+                          "tf": 1.4142135623730951
                         },
                         "7": {
                           "tf": 1.0
@@ -1728,7 +1836,7 @@
                             "df": 2,
                             "docs": {
                               "1": {
-                                "tf": 1.4142135623730952
+                                "tf": 1.4142135623730951
                               },
                               "7": {
                                 "tf": 1.0
@@ -1779,6 +1887,14 @@
                       "tf": 1.0
                     }
                   }
+                },
+                "k": {
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 1.7320508075688772
+                    }
+                  }
                 }
               }
             },
@@ -1805,7 +1921,7 @@
                             "t": {
                               "df": 1,
                               "docs": {
-                                "9": {
+                                "10": {
                                   "tf": 1.0
                                 }
                               }
@@ -1884,17 +2000,45 @@
                   "df": 2,
                   "docs": {
                     "4": {
-                      "tf": 1.4142135623730952
+                      "tf": 1.4142135623730951
                     },
                     "7": {
-                      "tf": 1.0
+                      "tf": 1.4142135623730951
                     }
                   }
                 }
               }
+            },
+            "o": {
+              "df": 0,
+              "docs": {},
+              "n": {
+                "df": 1,
+                "docs": {
+                  "9": {
+                    "tf": 1.0
+                  }
+                }
+              }
             }
           },
           "p": {
+            "a": {
+              "df": 0,
+              "docs": {},
+              "g": {
+                "df": 0,
+                "docs": {},
+                "e": {
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 2.0
+                    }
+                  }
+                }
+              }
+            },
             "df": 0,
             "docs": {},
             "r": {
@@ -1967,8 +2111,12 @@
                   "df": 0,
                   "docs": {},
                   "t": {
-                    "df": 0,
-                    "docs": {},
+                    "df": 1,
+                    "docs": {
+                      "9": {
+                        "tf": 2.0
+                      }
+                    },
                     "l": {
                       "df": 0,
                       "docs": {},
@@ -2031,7 +2179,7 @@
               "t": {
                 "df": 1,
                 "docs": {
-                  "9": {
+                  "10": {
                     "tf": 1.0
                   }
                 }
@@ -2063,7 +2211,15 @@
                 }
               },
               "df": 0,
-              "docs": {}
+              "docs": {},
+              "l": {
+                "df": 1,
+                "docs": {
+                  "9": {
+                    "tf": 1.4142135623730951
+                  }
+                }
+              }
             },
             "u": {
               "df": 0,
@@ -2122,13 +2278,16 @@
                   "docs": {},
                   "n": {
                     "d": {
-                      "df": 2,
+                      "df": 3,
                       "docs": {
                         "7": {
                           "tf": 1.0
                         },
                         "8": {
-                          "tf": 1.4142135623730952
+                          "tf": 1.4142135623730951
+                        },
+                        "9": {
+                          "tf": 1.0
                         }
                       }
                     },
@@ -2146,13 +2305,16 @@
                       "df": 0,
                       "docs": {},
                       "n": {
-                        "df": 2,
+                        "df": 3,
                         "docs": {
                           "3": {
-                            "tf": 1.4142135623730952
+                            "tf": 1.4142135623730951
                           },
                           "5": {
-                            "tf": 1.4142135623730952
+                            "tf": 1.4142135623730951
+                          },
+                          "9": {
+                            "tf": 1.0
                           }
                         }
                       }
@@ -2216,7 +2378,7 @@
                         "df": 1,
                         "docs": {
                           "7": {
-                            "tf": 1.4142135623730952
+                            "tf": 1.4142135623730951
                           }
                         }
                       }
@@ -2266,8 +2428,12 @@
                     "df": 0,
                     "docs": {}
                   },
-                  "df": 0,
-                  "docs": {}
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 1.4142135623730951
+                    }
+                  }
                 }
               },
               "x": {
@@ -2296,6 +2462,14 @@
               "r": {
                 "df": 0,
                 "docs": {},
+                "k": {
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 1.0
+                    }
+                  }
+                },
                 "l": {
                   "d": {
                     "df": 1,
@@ -2388,7 +2562,7 @@
                       "s": {
                         "df": 1,
                         "docs": {
-                          "9": {
+                          "10": {
                             "tf": 1.0
                           }
                         }
@@ -2511,6 +2685,26 @@
               }
             }
           },
+          "l": {
+            "df": 0,
+            "docs": {},
+            "i": {
+              "df": 0,
+              "docs": {},
+              "n": {
+                "df": 0,
+                "docs": {},
+                "k": {
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 1.0
+                    }
+                  }
+                }
+              }
+            }
+          },
           "n": {
             "df": 0,
             "docs": {},
@@ -2531,6 +2725,62 @@
               }
             }
           },
+          "p": {
+            "a": {
+              "df": 0,
+              "docs": {},
+              "g": {
+                "df": 0,
+                "docs": {},
+                "e": {
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 1.0
+                    }
+                  }
+                }
+              }
+            },
+            "df": 0,
+            "docs": {},
+            "r": {
+              "df": 0,
+              "docs": {},
+              "i": {
+                "df": 0,
+                "docs": {},
+                "n": {
+                  "df": 0,
+                  "docs": {},
+                  "t": {
+                    "df": 1,
+                    "docs": {
+                      "9": {
+                        "tf": 1.0
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          },
+          "r": {
+            "df": 0,
+            "docs": {},
+            "e": {
+              "df": 0,
+              "docs": {},
+              "l": {
+                "df": 1,
+                "docs": {
+                  "9": {
+                    "tf": 1.0
+                  }
+                }
+              }
+            }
+          },
           "s": {
             "df": 0,
             "docs": {},
@@ -2609,6 +2859,26 @@
                 }
               }
             }
+          },
+          "t": {
+            "df": 0,
+            "docs": {},
+            "e": {
+              "df": 0,
+              "docs": {},
+              "s": {
+                "df": 0,
+                "docs": {},
+                "t": {
+                  "df": 1,
+                  "docs": {
+                    "9": {
+                      "tf": 1.0
+                    }
+                  }
+                }
+              }
+            }
           }
         }
       }

tests/testing.rs

@@ -4,14 +4,8 @@ mod dummy_book;
 
 use dummy_book::DummyBook;
 
-use mdbook::book::Book;
-use mdbook::config::Config;
-use mdbook::errors::*;
-use mdbook::preprocess::{Preprocessor, PreprocessorContext};
 use mdbook::MDBook;
 
-use std::sync::{Arc, Mutex};
-
 #[test]
 fn mdbook_can_correctly_test_a_passing_book() {
     let temp = DummyBook::new().with_passing_test(true).build().unwrap();
@@ -27,30 +21,3 @@ fn mdbook_detects_book_with_failing_tests() {
 
     assert!(md.test(vec![]).is_err());
 }
-
-#[test]
-fn mdbook_runs_preprocessors() {
-    let has_run: Arc<Mutex<bool>> = Arc::new(Mutex::new(false));
-
-    struct DummyPreprocessor(Arc<Mutex<bool>>);
-
-    impl Preprocessor for DummyPreprocessor {
-        fn name(&self) -> &str {
-            "dummy"
-        }
-
-        fn run(&self, _ctx: &PreprocessorContext, _book: &mut Book) -> Result<()> {
-            *self.0.lock().unwrap() = true;
-            Ok(())
-        }
-    }
-
-    let temp = DummyBook::new().build().unwrap();
-    let cfg = Config::default();
-
-    let mut book = MDBook::load_with_config(temp.path(), cfg).unwrap();
-    book.with_preprecessor(DummyPreprocessor(Arc::clone(&has_run)));
-    book.build().unwrap();
-
-    assert!(*has_run.lock().unwrap())
-}