An object of class article has attributes such as title, author, abstract and date. The children of object article represent hierarchical structure, e.g., sectional units. The prologue of an article is its initial body, i.e., any text occurring before the first sectional unit. Though it would be cleaner to model such initial text as the first child, it is more convenient to handle it as an attribute. This is because La)TeX does not specify a complete document type definition (DTD) for articles. This lack of a fully specified DTD results in many of the objects not being well-defined. All objects that capture document content have the same basic model as described above for articles. Note also that LaTeX provides separate book and report styles. These styles differ from the article style mostly in the kind of layout achieved. The only structural difference is that books and reports in LaTeX can have chapters, while articles cannot. Chapters, sections and subsections are all structures that capture hierarchical document content and are modeled as sectional units. The article class of documents defined here therefore encompasses books and reports.
The leaves in the tree structure for documents represent actual content. Plain text is represented as a list of word objects, and inline mathematics is represented by object inline math. Each node in the document model is linked to its parent and siblings, enabling sophisticated browsing. These links are provided by the document base class.
Thus, class document provides the following slots:
The following is a brief overview of some of the document objects in our model. All of the following objects inherit from base class document.