Assignment CSA305 2000/2001

New Deadline: Wednesday 7th February.

This assignment is worth 30% of the marks for the credit.

1. Implement a grammar formalism that allows you to specify grammar rules, lexical entries and constraints in a DCG-like way. The main differences between your formalism and DCG is that it will permit the use of left recursive rules such as

   np(N) -> np(N1), [and], np(N2) { f(N,N1,N2) }.

   You will need to design a parsing algorithm which which can deal with such rules without going into a loop. [5 hours (30%)]

2. Look at these texts carefully. Give a brief overview to illustrate your understanding of the syntactic properties of the main sentence types and to motivate your answer to the next question. [2 hours (15%)]

3. Write a grammar/lexicon which covers all the sentences, and give a few examples of respective parse trees. [5 hours (30%)]

4. Modify your grammar so that for every complete parse of a given sentence it outputs a list of all head nouns of every NP in the sentence, so that for example

   ?- parse(['Clinton',signs,temporary,export,law],HeadNouns).
   HeadNouns=['Clinton',law]

   [3 hours (25%)].