RSTTool 2.4 - A markup Tool for Rhetorical Structure Theory

RSTTool is a graphical tool for annotating a text in terms of its rhetorical structure. The demonstration will show the various interfaces of the tool, focusing on its ease of use. 1 I n t r o d u c t i o n This paper describes the RSTTool, a graphical interface for marking up the structure of text. While primarily intended to be used for marking up Rhetorical Structure (cf. Rhetorical Structure Thegry (RST): Mann and Thompson (1988)), the tool also allows the mark-up of constituency-style analysis, as in Hasan's Generic Structure Potential (GSP cf. Hasan (1996)). The tool is written in the platform-independent scripting language, Tcl /Tk, and thus works under Windows, Macintosh, UNIX and LINUX operating systems. RSTTool is easy to use, one creates an RST diagram from a text by dragging from segment to segment, indicating rhetorical dependency. There is a separate interface for text segmentation. The tool can automatically segment at sentence boundaries (with reasonable accuracy), and the user clicks on the text to add boundaries missed by the automatic segmenter (or click on superfluous boundaries to remove them). The tool was previously described in O'Donnell (1997). However, since then tile tool has been substantially revised and extended,(the current version being 2.4). This version is also far more robust due to extensive debugging by one of RST's inventor's, Bill Mann. Particular improvements in the tool include: 1. GUI for defining relation: ability to add, rename, delete, etc. tile relations used using a graphical user interface. 2. St.atistical Analysis: a new interface was added. which allows users to be presented with statistits regarding the proportional use of relations in a text. 3. Output Options: the new tool allows saving of RST analyses in postscript (for inclusion in Latex documents), or sending diagrams directly to the printer. Files are now saved in an XML format, to facilitate importation in other systems. 4. Improved Structuring: the possibilities for structuring have improved, allowing the insertion of spans, multinuclear elements and schemas within existing structure. The Tool consists of four interfaces, which will be described in following sections: 1. Text Segmentation: for marking the boundaries between text segments; 2. Text Structuring: for marking the structural relations between these segments; 3. Relation Editor: for maintaining the set of discourse relations, and schemas; 4. Statistics: for deriving simple descriptive statistics based on the analysis. 2 W h a t is R S T T o o l F o r ? The RSTTool is an analysis tool, but most users of the tool are researchers in the text generation field. For this reason, we present the tool at this conference. Several reasons for using the tool are: . Corpus Studies: before one can generate text, one nmst understand the rhetorical patterns of language. By performing analyses of texts sin> ilar to which one wishes to generate, one can identify the recurrent structures in tile text-type and work towards understanding their context of use. o Results Verification: often, a particular study may be challenged by other researchers. If the study was performed using RSTTool, the corpus supporting the study can be released for analysis by others. Previously, most RST analysis was done bv hand, malting distribution of