TOC is provided by the user in a YAML file. When it is read, a data structure is created that represents the TOC data. This data structure is defined below. It is a basic hierarchical list structure that consist of nodes that correspond to sections in the documentation.

namespace LiterateCS.Theme
{
using System.Collections.Generic;


Table of contents has two lists inside it. The first one contains the top-level sections in a hierarchical structure. The second one is a computed field that contains the same sections in a flat list. The flattened list helps us find quickly the previous and next entry for a given section.

	public class Toc
{
private List<Section> _contents;
private List<Section> _flattened;


The method that flattens the contents traverses the data structure recursively and add each section to the flat list.

		private void FlattenContents (List<Section> sections, List<Section> flattened)
{
foreach (var section in sections)
{
if (section.File != null)
if (section.Subs != null)
FlattenContents (section.Subs, flattened);
}
}


The Contents property can be set outside the class. When it is set, the flattened list is recomputed. The Flattened property is read-only.

		public List<Section> Contents
{
get { return _contents; }
set
{
_contents = value;
_flattened = new List<Section> ();
FlattenContents (_contents, _flattened);
}
}

public List<Section> Flattened
{
get { return _flattened; }
}


When we have the flattened list of topics available, we can find the next and previous section in the list easily. We by just search for the index of the section and return the next or previous based on the index. If we cannot find the section, or we are at the beginning or end of the list, we return null.

		public Section NextSection (Section current)
{
var i = _flattened.IndexOf (current);
return i < 0 || i >= _flattened.Count - 1 ?
null :
_flattened[i + 1];
}

public Section PreviousSection (Section current)
{
var i = _flattened.IndexOf (current);
return i <= 0 ?	null : _flattened[i - 1];
}
}


## Section Class

The Section object represents an individual entry in TOC. There might be a file that corresponds to the section, but not necessarily. A section can be used also to logically group pages under a same topic without providing a separate page for it. In this case you cannot jump to the section, but you can still see it in TOC.

	public class Section
{


The Page property is the title of the section. It is a short string containing usually the first heading in the file.

		public string Page { get; set; }


The relative path to the source file is stored in the File property. It is naturally unique within TOC. There cannot be two sections pointing to the same file. It can be null, though. As explained above, there can be sections without files.

		public string File { get; set; }


You can provide additional description about the section. This data is optional and may be omitted when showing the TOC.

		public string Desc { get; set; }


Subsections are stored in a list. If there are no subsections under the current section the property is null.

		public List<Section> Subs { get; set; }


Custom string conversion is provided mainly for debugging purposes.

		public override string ToString ()
{
return string.Format ("{0} -> {1}", Page, File);
}
}
}