<p>
A document is composed of one or several <em>blocks</em>. A block correspond roughly to a html page, but it is also possible to insert one or more blocks into another.
</p><p>
Each block must have a name (a unique word) and a title. The entry point of the document is a block under the name <span class="tt wims_code_words">main</span>. It is this block which leads the readers to the entire content of the document.
</p>
<h3 id="creation">Creation of a block</h3>
To create a new block (except the entrance block <span class="tt wims_code_words">main</span>), you should first cite it in an existing block. When you read the latter, the citation becomes a link that leads you to the creation of the new block.
<p>
There are three wayt for a block to cite another one.
</p><ol>
<li>By a link. \link{link,The syntax of link}
is very simple: it is enough to give the name of the cited block.
One may also use links to cite blocks of other documents.
</li><li>As a foldable part of the citing block. This part may be folded in and out as the readers wish.
 \link{fold,The syntax}.
</li><li>As a transparently inserted part of the citing block.
\link{embed, The syntax}.
</li></ol>
<h3 id="navigation">Fields "previous", "next" and "parent" of a block</h3>
The name of a block af the document has to be written in the fields "previous", "next" and "parent" of each block.
These fields are used to
<ul> define the structure of the document.
<li>provide a reading order of all pages of the document (for instance, the reader could use the arrow <span class="text_icon doch_next">Next</span> to go to the next block of the block where it is; he could used the arrow <span class="text_icon doch_up">Sup</span> to go back to the parent block of the block he reads) ;</li>
<li> define the blocks that appear in the printable version of the document: blocks appear in the printable version if and only if there is a link to them in their parent block and they appear in the link order (printable version is useful for example to search a word in a document).</li>
</ul>
