Add a config option to disable section numbers in the TOC.

book-example/src/format/config.md

@@ -35,6 +35,8 @@ This is general information about your book.
 - **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.
+- **section-numbers:** By default, sections are numbered in the table of
+  contents. Setting this to `false` disables numbering.
 
 **book.toml**
 ```toml
@@ -43,6 +45,7 @@ title = "Example book"
 authors = ["John Doe", "Jane Doe"]
 description = "The example book covers examples."
 src = "my-src"  # the source files will be found in `root/my-src` instead of `root/src`
+section-numbers = false
 ```
 
 ### Build options

src/config.rs

@@ -209,6 +209,8 @@ pub struct BookConfig {
     pub src: PathBuf,
     /// Does this book support more than one language?
     pub multilingual: bool,
+    /// Should sections be numbered in the TOC?
+    pub section_numbers: bool,
 }
 
 impl Default for BookConfig {
@@ -219,6 +221,7 @@ impl Default for BookConfig {
             description: None,
             src: PathBuf::from("src"),
             multilingual: false,
+            section_numbers: true,
         }
     }
 }
@@ -274,6 +277,7 @@ mod tests {
         description = "A completely useless book"
         multilingual = true
         src = "source"
+        section-numbers = false
 
         [build]
         build-dir = "outputs"
@@ -300,6 +304,7 @@ mod tests {
             description: Some(String::from("A completely useless book")),
             multilingual: true,
             src: PathBuf::from("source"),
+            section_numbers: false,
             ..Default::default()
         };
         let build_should_be = BuildConfig {

src/renderer/html_handlebars/hbs_renderer.rs

@@ -407,9 +407,15 @@ fn make_data(book: &MDBook, config: &Config) -> Result<serde_json::Map<String, s
                 chapter.insert("path".to_owned(), json!(path));
             }
             BookItem::Chapter(ref s, ref ch) => {
-                let section = s.iter()
+                let level = format!("{}", s.len());
-                               .fold("".to_owned(), |s, i| s + &i.to_string() + ".");
+                chapter.insert("level".to_owned(), json!(level));
-                chapter.insert("section".to_owned(), json!(section));
+
+                if config.book.section_numbers {
+                    let section = s.iter()
+                                   .fold("".to_owned(), |s, i| s + &i.to_string() + ".");
+                    chapter.insert("section".to_owned(), json!(section));
+                }
+
                 chapter.insert("name".to_owned(), json!(ch.name));
                 let path = ch.path.to_str().ok_or_else(|| {
                                                            io::Error::new(io::ErrorKind::Other,

src/renderer/html_handlebars/helpers/toc.rs

@@ -34,8 +34,8 @@ impl HelperDef for RenderToc {
                 continue;
             }
 
-            let level = if let Some(s) = item.get("section") {
+            let level = if let Some(s) = item.get("level") {
-                s.matches('.').count()
+                s.parse().expect(&format!("Error: level expected integer, got \"{}\"", s))
             } else {
                 1
             };