1 files changed, 69 insertions, 3 deletions

diff --git a/lib/backbone/summary.js b/lib/backbone/summary.js
index aa52104..5775c8b 100644
--- a/lib/backbone/summary.js
+++ b/lib/backbone/summary.js
@@ -14,6 +14,7 @@ It's defined by a title, a reference, and children articles, the reference (ref)
 function TOCArticle(summary, title, ref, articles, parent) {
     this.summary = summary;
     this.title = title;
+    this.parent = parent;
 
     if (ref && location.isExternal(ref)) {
         throw error.ParsingError(new Error('SUMMARY can only contains relative locations'));
@@ -50,6 +51,45 @@ TOCArticle.prototype.hasChildren = function() {
     return this.articles.length > 0;
 };
 
+// Return true if has an article as parent
+TOCArticle.prototype.hasParent = function() {
+    return (this.parent instanceof TOCArticle);
+};
+
+// Return next article in the TOC
+TOCArticle.prototype.next = function() {
+    var parentsArticles = this.parent.articles;
+    var pos = _.findIndex(parentsArticles, this);
+
+    if ((pos + 1) >= parentsArticles.length) {
+        if (this.hasParent()) {
+            return this.parent.next();
+        } else {
+            return null;
+        }
+    } else {
+        // next has the same parent
+        return parentsArticles[pos + 1];
+    }
+};
+
+// Return previous article in the TOC
+TOCArticle.prototype.prev = function() {
+    var parentsArticles = this.parent.articles;
+    var pos = _.findIndex(parentsArticles, this);
+
+    if ((pos - 1) < 0) {
+        if (this.hasParent()) {
+            return this.parent.prev();
+        } else {
+            return null;
+        }
+    } else {
+        // prev has the same parent
+        return parentsArticles[pos - 1];
+    }
+};
+
 /*
 A part of a ToC is a composed of a tree of articles.
 */
@@ -58,14 +98,17 @@ function TOCPart(summary, part) {
 
     this.summary = summary;
     this.articles = _.map(part.articles || part.chapters, function(article) {
-        return new TOCArticle(that.summary, article.title, article.path, article.articles);
-    });
+        return new TOCArticle(that.summary, article.title, article.path, article.articles, this);
+    }, this);
 }
 
 // Iterate over all entries of the part
 TOCPart.prototype.walk = function(iter) {
     _.each(this.articles, function(article) {
-        iter(article);
+        if (iter(article) === false) {
+            return false;
+        }
+
         article.walk(iter);
     });
 };
@@ -109,6 +152,29 @@ Summary.prototype.walk = function(iter) {
     });
 };
 
+// Find a specific article using a filter
+Summary.prototype.find = function(filter) {
+    var result;
+
+    this.walk(function(article) {
+        if (filter(article)) {
+            result = article;
+            return false;
+        }
+    });
+
+    return result;
+};
+
+// Return the first TOCArticle for a specific page (or path)
+Summary.prototype.getByPage = function(page) {
+    if (!_.isString(page)) page = page.path;
+
+    return this.find(function(article) {
+        return article.path == page;
+    });
+};
+
 // Return the count of articles in the summary
 Summary.prototype.count = function() {
     return this._length;