Lehner's Prolog Tree Drawing Program


Prof. Ray C. Dougherty
New York University | Linguistics Department

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Note from Christoph Lehner

What Does This Program Do?
How Do I Download and Execute the Program?
Writing the Tree Diagram to Disk
How to Run chris.pl with a Standard DCG.
Examples of Small Fragments of German in DCG.

What Does This Program Do?

Christoph Lehner (Mail) has a tree drawing program (SWI Prolog version) that works in Prolog to yield a tree that can be viewed on an ascii terminal or sent to a disk file and printed.

This program produces a phrase marker that can be displayed on a screen or written to a disk file that can be incoporated into a word processor document or a WWW page, see Workbook 2.2.. For the sentence The man sees in the house it produces this tree.

The input of the tree drawing program is a standard prolog structure representing a linguistic syntax tree (hint: A.Colmerauer - the inventor of Prolog - uses to call Prolog structures 'trees', anyways). A typical call yielding the graphical output shown above is:

?- drucke_baum(s(np(det(the),n(man)),vp(v(sees),pp(p(in),np(det(the),n(house)))))).

The structure is normally produced automatically by a syntactic parser. It is not easy to read. That's what the tree drawing program is meant for, i.e. graphically displaying structures like the one shown.

If you load the program chris.pl it will display sample trees, see below. Christoph's program can be used to view the output of the Prolog parsers on this site. By routing the screen to a file, one can obtain trees that may be printed and incorporated into documents.

If you have trouble using any of these program, or if you would like more documentation, please let us know lehner@cl.uni-hildesheim.de.

How Do I Download and Execute the Program?