rust-lang · Michael-F-Bryan · Nov 12, 2017 · Sep 30, 2017 · Sep 30, 2017 · Sep 30, 2017
diff --git a/book-example/src/format/config.md b/book-example/src/format/config.md
@@ -2,14 +2,10 @@
 
 You can configure the parameters for your book in the ***book.toml*** file.
 
->**Note:**  
-JSON configuration files were previously supported but have been deprecated in favor of 
-the TOML configuration file. If you are still using JSON we strongly encourage you to migrate to
-the TOML configuration because JSON support will be removed in the future.
-
 Here is an example of what a ***book.toml*** file might look like:
 
 ```toml
+[book]
 title = "Example book"
 author = "John Doe"
 description = "The example book covers examples."
@@ -24,66 +20,118 @@ additional-css = ["custom.css"]
 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
 
-- **title:** The title of the book
-- **author:** The author of the book
-- **description:** A description for the book, which is added as meta information in the html `<head>` of each page
-
-**book.toml**
-```toml
-title = "Example book"
-author = "John Doe"
-description = "The example book covers examples."
-```
+### General metadata
 
-Some books may have multiple authors, there is an alternative key called `authors` plural that lets you specify an array
-of authors.
+This is general information about your book.
 
-**book.toml**
-```toml
-title = "Example book"
-authors = ["John Doe", "Jane Doe"]
-description = "The example book covers examples."
-```
-
-### Source directory
-By default, the source directory is found in the directory named `src` directly under the root folder. But this is configurable
-with the `source` key in the configuration file.
+- **title:** The title of the book
+- **authors:** The author(s) of the book
+- **description:** A description for the book, which is added as meta
+  information in the html `<head>` of each page
+- **src:** By default, the source directory is found in the directory named
+  `src` directly under the root folder. But this is configurable with the `src`
+  key in the configuration file.
+- **build-dir:** The directory to put the rendered book in. By default this is
+  `book/` in the book's root directory.
 
 **book.toml**
 ```toml
+[book]
 title = "Example book"
 authors = ["John Doe", "Jane Doe"]
 description = "The example book covers examples."
-
-source = "my-src"  # the source files will be found in `root/my-src` instead of `root/src`
+src = "my-src"  # the source files will be found in `root/my-src` instead of `root/src`
+build-dir = "build"
 ```
 
 ### HTML renderer options
-The HTML renderer has a couple of options aswell. All the options for the renderer need to be specified under the TOML table `[output.html]`.
+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:
 
-- **`destination`:** By default, the HTML book will be rendered in the `root/book` directory, but this option lets you specify another
-  destination fodler.
-- **`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.
-- **`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.
+    pub playpen: Playpen,
+
+- **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.
+- **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.
+- **playpen:** A subtable for configuring various playpen settings.
 
 **book.toml**
 ```toml
+[book]
 title = "Example book"
 authors = ["John Doe", "Jane Doe"]
 description = "The example book covers examples."
 
 [output.html]
-destination = "my-book" # the output files will be generated in `root/my-book` instead of `root/book`
 theme = "my-theme"
 curly-quotes = true
 google-analytics = "123456"
 additional-css = ["custom.css", "custom2.css"]
 additional-js = ["custom.js"]
+
+[output.html.playpen]
+editor = "./path/to/editor"
+editable = false
 ```
 
+
+## For Developers
+
+If you are developing a plugin or alternate backend then whenever your code is
+called you will almost certainly be passed a reference to the book's `Config`. 
+This can be treated roughly as a nested hashmap which lets you call methods like
+`get()` and `get_mut()` to get access to the config's contents.
+
+By convention, plugin developers will have their settings as a subtable inside
+`plugins` (e.g. a link checker would put its settings in `plugins.link_check`) 
+and backends should put their configuration under `output`, like the HTML 
+renderer does in the previous examples.
+
+As an example, some hypothetical `random` renderer would typically want to load
+its settings from the `Config` at the very start of its rendering process. The
+author can take advantage of serde to deserialize the generic `toml::Value` 
+object retrieved from `Config` into a struct specific to its use case.
+
+```rust
+#[derive(Debug, Deserialize, PartialEq)]
+struct RandomOutput {
+    foo: u32,
+    bar: String,
+    baz: Vec<bool>,
+}
+
+let src = r#"
+[output.random]
+foo = 5
+bar = "Hello World"
+baz = [true, true, false]
+"#;
+
+let book_config = Config::from_str(src)?; // usually passed in by mdbook
+let random: Value = book_config.get("output.random").unwrap_or_default();
+let got: RandomOutput = random.try_into()?;
+
+assert_eq!(got, should_be);
+
+if let Some(baz) = book_config.get_deserialized::<Vec<bool>>("output.random.baz") {
+  println!("{:?}", baz); // prints [true, true, false]
+
+  // do something interesting with baz
+}
+
+// start the rendering process
+```
diff --git a/src/bin/build.rs b/src/bin/build.rs
@@ -1,4 +1,5 @@
-use clap::{App, ArgMatches, SubCommand};
+use std::path::PathBuf;
+use clap::{ArgMatches, SubCommand, App};
 use mdbook::MDBook;
 use mdbook::errors::Result;
 use {get_book_dir, open};
@@ -15,10 +16,6 @@ pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
         .arg_from_usage(
             "--no-create 'Will not create non-existent files linked from SUMMARY.md'",
         )
-        .arg_from_usage(
-            "--curly-quotes 'Convert straight quotes to curly quotes, except for those \
-             that occur in code blocks and code spans'",
-        )
         .arg_from_usage(
             "[dir] 'A directory for your book{n}(Defaults to Current Directory \
              when omitted)'",
@@ -28,21 +25,16 @@ pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
 // Build command implementation
 pub fn execute(args: &ArgMatches) -> Result<()> {
     let book_dir = get_book_dir(args);
-    let book = MDBook::new(&book_dir).read_config()?;
+    let mut book = MDBook::new(&book_dir).read_config()?;
 
-    let mut book = match args.value_of("dest-dir") {
-        Some(dest_dir) => book.with_destination(dest_dir),
-        None => book,
-    };
+    if let Some(dest_dir) = args.value_of("dest-dir") {
+        book.config.book.build_dir = PathBuf::from(dest_dir);
+    }
 
     if args.is_present("no-create") {
         book.create_missing = false;
     }
 
-    if args.is_present("curly-quotes") {
-        book = book.with_curly_quotes(true);
-    }
-
     book.build()?;
 
     if args.is_present("open") {

diff --git a/src/bin/init.rs b/src/bin/init.rs
@@ -47,7 +47,7 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
     }
 
     // Because of `src/book/mdbook.rs#L37-L39`, `dest` will always start with `root`
-    let is_dest_inside_root = book.get_destination().starts_with(book.get_root());
+    let is_dest_inside_root = book.get_destination().starts_with(&book.root);
 
     if !args.is_present("force") && is_dest_inside_root {
         println!("\nDo you want a .gitignore to be created? (y/n)");

diff --git a/src/bin/serve.rs b/src/bin/serve.rs
@@ -3,7 +3,7 @@ extern crate staticfile;
 extern crate ws;
 
 use std;
-use std::path::Path;
+use std::path::PathBuf;
 use self::iron::{status, AfterMiddleware, Chain, Iron, IronError, IronResult, Request, Response,
                  Set};
 use clap::{App, ArgMatches, SubCommand};
@@ -29,10 +29,6 @@ pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
             "-d, --dest-dir=[dest-dir] 'The output directory for \
              your book{n}(Defaults to ./book when omitted)'",
         )
-        .arg_from_usage(
-            "--curly-quotes 'Convert straight quotes to curly quotes, except \
-             for those that occur in code blocks and code spans'",
-        )
         .arg_from_usage("-p, --port=[port] 'Use another port{n}(Defaults to 3000)'")
         .arg_from_usage(
             "-w, --websocket-port=[ws-port] 'Use another port for the \
@@ -53,15 +49,10 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
     const RELOAD_COMMAND: &'static str = "reload";
 
     let book_dir = get_book_dir(args);
-    let book = MDBook::new(&book_dir).read_config()?;
-
-    let mut book = match args.value_of("dest-dir") {
-        Some(dest_dir) => book.with_destination(Path::new(dest_dir)),
-        None => book,
-    };
+    let mut book = MDBook::new(&book_dir).read_config()?;
 
-    if args.is_present("curly-quotes") {
-        book = book.with_curly_quotes(true);
+    if let Some(dest_dir) = args.value_of("dest-dir") {
+        book.config.book.build_dir = PathBuf::from(dest_dir);
     }
 
     let port = args.value_of("port").unwrap_or("3000");
@@ -73,8 +64,7 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
     let address = format!("{}:{}", interface, port);
     let ws_address = format!("{}:{}", interface, ws_port);
 
-    book.set_livereload(format!(
-        r#"
+    book.livereload = Some(format!(r#"
     <script type="text/javascript">
         var socket = new WebSocket("ws://{}:{}");
         socket.onmessage = function (event) {{

diff --git a/src/bin/watch.rs b/src/bin/watch.rs
@@ -1,6 +1,6 @@
 extern crate notify;
 
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use self::notify::Watcher;
 use std::time::Duration;
 use std::sync::mpsc::channel;
@@ -18,10 +18,6 @@ pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
             "-d, --dest-dir=[dest-dir] 'The output directory for \
              your book{n}(Defaults to ./book when omitted)'",
         )
-        .arg_from_usage(
-            "--curly-quotes 'Convert straight quotes to curly quotes, except \
-             for those that occur in code blocks and code spans'",
-        )
         .arg_from_usage(
             "[dir] 'A directory for your book{n}(Defaults to \
              Current Directory when omitted)'",
@@ -31,15 +27,10 @@ pub fn make_subcommand<'a, 'b>() -> App<'a, 'b> {
 // Watch command implementation
 pub fn execute(args: &ArgMatches) -> Result<()> {
     let book_dir = get_book_dir(args);
-    let book = MDBook::new(&book_dir).read_config()?;
+    let mut book = MDBook::new(&book_dir).read_config()?;
 
-    let mut book = match args.value_of("dest-dir") {
-        Some(dest_dir) => book.with_destination(dest_dir),
-        None => book,
-    };
-
-    if args.is_present("curly-quotes") {
-        book = book.with_curly_quotes(true);
+    if let Some(dest_dir) = args.value_of("dest-dir") {
+        book.config.book.build_dir = PathBuf::from(dest_dir);
     }
 
     if args.is_present("open") {
@@ -84,18 +75,17 @@ where
     };
 
     // Add the theme directory to the watcher
-    watcher.watch(book.get_theme_path(), Recursive)
+    watcher.watch(book.theme_dir(), Recursive)
            .unwrap_or_default();
 
-
     // Add the book.{json,toml} file to the watcher if it exists, because it's not
     // located in the source directory
-    if watcher.watch(book.get_root().join("book.json"), NonRecursive)
+    if watcher.watch(book.root.join("book.json"), NonRecursive)
               .is_err()
     {
         // do nothing if book.json is not found
     }
-    if watcher.watch(book.get_root().join("book.toml"), NonRecursive)
+    if watcher.watch(book.root.join("book.toml"), NonRecursive)
               .is_err()
     {
         // do nothing if book.toml is not found