Logic Programming 06-25433 Autumn 2012

Lecture 5: manipulating atomics and clauses reading input from the keyboard using recursion; looking words up in a dictionary; building a simple morphological analyser using sub_atom/5; using Prolog's operator notation to make code more readable; using clause/2 to access clauses in the Prolog program, for instance to display them in some helpful layout.

How to prepare   Ensure you understand why recursion requires (at least): one base (terminating) clause one recursive clause; find definitions of functor/3, arg/3 and clause/2; try examples of these predicates by typing queries in the Prolog interpreter.

Video   Recording of the lecture (Vimeo)

Slides   If you really want the slides from the lecture ... 1 slide per page 6 slides per page but don't forget printing the slides is not the same as understanding them.

Summary   Summary and programs with commentary from the lecture

Programs from the lecture   Example 1 - using recursion in reading in text Example 2 - looking words up in a dictionary Example 3 - using a morphological analyser Example 4 - making dictionary entries more readable (by humans) Example 5 - pretty printing a Prolog clause

Individual study suggestions and further reading   Study how to represent information, search strategies and simple rules and how non-deterministic problems can be described and processed in Prolog. An introduction to morphology (Described by Jocelyn Payne as "Another nice introduction, which explains why the possessive suffix 's is a problem that breaks the modularity of some analysers.") Recursion is covered in: Bratko. 3rd ed. Sections 1.3-1.4; 2.5-2.6, pp 14-22; 46-57. Clocksin & Mellish. Chapter 3, sections 3.1-3.4, pp 43-53. Covington. Chapter 4, sections 4.10-4.13, pp 103-111. Sterling & Shapiro. Chapter 3, section 3.1, pp 45-56.

Assessed work associated with this lecture   Tutorial sheet 3