Levels of document syntax

• Character
• Token
• Text objects: Markup and text
  • word and sentence
  • blocks: paragraph, list, table
  • hierarchies: chapters, sections, subsections
  • re-entrancies: glossary, bibliography, index
  • isomorphisms: table of contents

The basic model of text description languages is graphs:

• strings,
• trees,
• directed acyclic graphs,
• directed cyclic graphs,
• non-planar graphs, ...

from the character up to the entire document.