From cd3b37593b52853485d85e29ec02ddc233cfaf0e Mon Sep 17 00:00:00 2001
From: Chris Spiegel <cspiegel@gmail.com>
Date: Tue, 5 Dec 2017 18:53:17 -0800
Subject: [PATCH] Track the current section as a vector of i32 rather than a
 String.

The vector is the "natural" format of the section (i.e. how it is
initially created) and is more suitable for further processing than a
string is. Creation of a string representation of the section is delayed
until it's actually required.
---
 src/book/bookitem.rs                         | 3 ++-
 src/parse/summary.rs                         | 6 ++----
 src/renderer/html_handlebars/hbs_renderer.rs | 4 +++-
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/book/bookitem.rs b/src/book/bookitem.rs
index a2ec2cb0..c33804aa 100644
--- a/src/book/bookitem.rs
+++ b/src/book/bookitem.rs
@@ -2,10 +2,11 @@ use serde::{Serialize, Serializer};
 use serde::ser::SerializeStruct;
 use std::path::PathBuf;
 
+type Section = Vec<i32>;
 
 #[derive(Debug, Clone)]
 pub enum BookItem {
-    Chapter(String, Chapter), // String = section
+    Chapter(Section, Chapter),
     Affix(Chapter),
     Spacer,
 }
diff --git a/src/parse/summary.rs b/src/parse/summary.rs
index 1193b6f5..b4434ea5 100644
--- a/src/parse/summary.rs
+++ b/src/parse/summary.rs
@@ -110,9 +110,7 @@ fn parse_level(summary: &mut Vec<&str>,
                         // Increment section
                         let len = section.len() - 1;
                         section[len] += 1;
-                        let s = section.iter()
-                                       .fold("".to_owned(), |s, i| s + &i.to_string() + ".");
-                        BookItem::Chapter(s, ch)
+                        BookItem::Chapter(section.clone(), ch)
                     }
                     _ => parsed_item,
                 }
@@ -181,7 +179,7 @@ fn parse_line(l: &str) -> Option<BookItem> {
                 debug!("[*]: Line is list element");
 
                 if let Some((name, path)) = read_link(line) {
-                    return Some(BookItem::Chapter("0".to_owned(), Chapter::new(name, path)));
+                    return Some(BookItem::Chapter(vec![0], Chapter::new(name, path)));
                 } else {
                     return None;
                 }
diff --git a/src/renderer/html_handlebars/hbs_renderer.rs b/src/renderer/html_handlebars/hbs_renderer.rs
index 14e45c23..2dbe3231 100644
--- a/src/renderer/html_handlebars/hbs_renderer.rs
+++ b/src/renderer/html_handlebars/hbs_renderer.rs
@@ -407,7 +407,9 @@ 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) => {
-                chapter.insert("section".to_owned(), json!(s));
+                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,