<\body> documents> Whereas document fragments can be general trees, documents are trees of a special form which we will describe now. The root of a document is necessarily a tag. The children of this tag are necessarily of one of the following forms: <\explain| version>> This mandatory tag specifies the version of which was used to save the document. <\explain|> An optional project to which the document belongs. <\explain> >|pack-n>>> <|explain> An optional style and additional packages for the document. <\explain|> This mandatory tag specifies the body of your document. <\explain|> Optional specification of the initial environment for the document, with information about the page size, margins, . The is of the form >|binding-n>. Each i> is of the form and associates the initial value to the environment variable . The initial values of environment variables which do not occur in the table are determined by the style file and packages. <\explain|> An optional list of all valid references to labels in the document. Even though this information can be automatically recovered by the typesetter, this recovery requires several passes. In order to make the behaviour of the editor more natural when loading files, references are therefore stored along with the document. The is of a similar form as above. In this case a tuple is associated to each label. This tuple is either of the form or . The corresponds to the displayed text when referring to the label, to the corresponding page number, and the optional to the file where the label was defined (this is only used when the file is part of a project). <\explain|> This optional tag specifies all auxiliary data attached to the document. Usually, such auxiliary data can be recomputed automatically from the document, but such recomputations may be expensive and even require tools which are not necessarily installed on your system. The , which is specified in a similar way as above, associates auxiliary content to a key. Standard keys include , , , , <\example> An article with the simple text ``hello world!'' is represented as <\equation*> >|>|>>|>|article>|>|>|hello world!>>> <\initial> <\collection>