Planning texts by constraint satisfaction

A method is described by which a rhetorical-structure tree can be realized by a text structure made up of sections, paragraphs, sentences, vertical lists, and other textual patterns, with discourse connectives added (in the correct positions) to mark rhetorical relations. We show that text-structuring can be formulated as a Constraint Satisfaction Problem, so that all solutions respecting constraints on text-structure formation and structural compatibility can be efficiently generated. Of the many solutions generated by this method, some are stylistically preferable to others; we show how further constraints can be applied in order to select the best versions. Finally, we discuss some extensions such as the generation of indented text structures.